THE  LIBRARY 

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Vol.  Xffl  SEPTEMBER,  1311 

No.   4  PSYCHOLOGICAL  REVIEW  PUBLICATIONS  Whole  No.  56 


THE 

Psychological  Monographs 


EDITED  BY 

JAMES  R.  ANGELL,  UNIVERSITY  OF  CHICAGO 
HOWARD  C.  WARREN,  PRINCETON  UNIVERSITY  (Index) 

JOHN  B.  WATSON,  JOHNS  HOPKINS  UNIVERSITY  (Review)  and 
ARTHUR  H.  PIERCE,  SMITH  COLLEGE  (Bulletin) 


On  the  Functions  of  the  Cerebrum:  the  Occipital  Lobes. 

Shepherd  Ivory    Franz,    Ph.D., 

Research  Assistant  of  the  Carnegie  Institution  of  Washington ; 

Scientific  Director  and  Psychologist,  Government  Hospital  for  the  Insane ; 

Professor  of  Physiology,  George  Washington  University. 

with  the  cooperation  of 

Gonzalo  R.   Lafora,  M.D., 
Histopathologist,  Government  Hospital  for  the  Insane. 


PSYCHOLOGICAL    REVIEW    COMPANY 

PRINCETON,  N.  J., 
BALTIMORE,  MD.  AND  LANCASTER,  PA. 

AGENTS  :   G.  E.  STECHERT  &  CO.,  LONDON  (2  Star  Yard,  Carey  St.,  W.  C.;) 
LEIPZIG  (Hospital  St.,  10);  PARIS  (76  rue  de  Rennes) 

-i    '•>    j     1    -|    ; 

1  6  1 1   I 


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ftouedicaj 
Libra? 


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CONTENTS. 

Introduction  ......................  .  .....................  I 

The  occipital  lobes  ........................................  3 

The  localization  of  function  in  the  occipital  lobe  ..............  9 

Movement  .".  ........................................  9 

Sensation  .....  1  1 
S 

^              Perceptions,  etc.  .  .  ....................................  22 


Experimental  24 

Introduction 24 

Methods    26 

Training   26 

Operation   38 

Post-mortem  examination 40 

Results    44 

Discussion  of  results 100 

Summary  and  conclusions 112 

References    .                                                                                       .  n-v 


INTRODUCTION1 

The  positive  statements  regarding  the  functions  of  the  occipital 
lobes  might  lead  one  unacquainted  with  the  facts  to  believe  that 
the  functions  of  these  portions  of  the  cerebrum  were  well  under- 
stood. A  careful  consideration  of  the  experimental  and  clinical 
phenomena  accompanying  disturbances  in  these  areas  does  not 
support  the  general  belief,  and  although  they  are  among  the  first 
parts  of  the  brain  to  have  been  investigated  by  physiological 
methods  there  remains  much  to  be  done  before  we  may  say  we 
understand  their  function  and  their  method  of  working.  We  may 
apply  directly  to  this  region  of  the  cerebrum  the  statement  of 
Hitzig,  made  a  decade  ago  in  regard  to  the  whole  brain:  "Die 
Hirnrinde  und  ihre  Zusammenwirkung  mit  ihre  subcortikalen 
Centren  stellen  vielmehr  noch  heute  einen  dunklen  Continent 
vor  (31)."  That  to  some  extent  and  in  some  manner  the  cortex 
in  the  occipital  portion  of  the  brain  functions  in  connection  with 
the  retinae  is  probably  true,  but  how  it  functions  and  in  what 
manner  it  is  connected  with  the  retinae  have  not  been  determined 

1The  present  work  was  made  possible  by  a  grant  from  the  Carnegie  In- 
stitution of  Washington  to  the  author  as  research  assistant.  This  assistance 
is  hereby  acknowledged  and  the  author  expresses  his  sense  of  obligation  for 
it.  On  the  histological  side  of  the  work  the  author  has  had  the  opportunity 
of  the  cooperation  of  Drs.  N.  Achiicarro  and  Gonzalo  R.  Lafora,  respectively 
former  and  present  histopathologist  at  this  institution.  Assistance  in  the 
observation  and  in  the  training  of  the  monkeys  has  been  given  especially  by 
Dr.  A.  H.  Sutherland,  formerly  of  this  institution  and  now  of  the  University 
of  Illinois,  and  by  Drs.  Achiicarro,  Barnes,  Blackburn,  and  Lafora  and  their 
assistance  is  hereby  gratefully  acknowledged. 

The  present  work  deals  mainly  with  the  lateral  portions  of  the  occipital 
lobes,  and  it  is  expected  that  articles  will  appear  later  dealing  with  the 
mesial  aspect  and  with  the  results  of  electrical  stimulation. 

While  this  article  was  in  manuscript  form  there  appeared  von  Bech- 
terew's  Ueber  die  Funktionen  der  Nervencentra,  which  contains  a  resume 
of  much  work  on  the  occipital  lobes.  Von  B.  discusses  to  great  length  the 
work  of  Goltz,  of  Munk  and  of  Luciani  but  slights  much  which  is  discussed 
in  pp.  9-23. 


2  SHEPHERD   IVORY  FRANZ 

to  the  complete  satisfaction  of  those  who  have  most  carefully 
investigated  the  matter. 

The  numerous  recent  histological  studies  of  the  architecture 
of  the  cerebral  cortex  emphasizes  the  fact  that  the  clinical  and 
physiological  problems  of  the  localization  of  function  are  not 
simple,  either  in  method  or  in  interpretation.  Although  there  is 
considerable  diversity  in  the  results  of  the  different  histological 
investigators,  there  is,  on  the  other  hand,  sufficient  uniformity  to 
indicate  that  the  old  landmarks  of  the  cerebrum  must  be  given  up 
and  that  the  facts  must  be  viewed  in  connection  with  the  plans 
made  by  recent  surveys.  Most  of  the  fissures,  especially  those  of 
a  secondary  character,  are  of  little  value  for  the  limitation  of 
special  areas,  and  it  is  necessary  at  the  present  time  to  considei 
the  areas  from  an  entirely  different  standpoint.  This  standpoint 
is  the  intimate  structure  of  the  cortex,  the  number  and  grouping 
of  the  cells,  the  arrangements  of  the  fibers,  and  the  combination 
of  these.  It  has  been  shown  that  we  may  almost  entirely  dis- 
regard the  cerebral  fissures  and  divide  the  cortex  of  the  cerebrum 
into  approximately  fifteen  areas,  each  with  an  histological  struct- 
ure quite  distinct  and  different  from  those  of  the  surrounding 
areas. 

The  histological  studies  have  led  to  the  formulation  of  hy- 
potheses regarding  the  probable  function  of  the  parts  and  the 
statement  is  made  that  each  of  the  areas  histologically  distinct  is 
also  physiologically  different  from  the  bordering  areas.  Although 
all  the  histologists  appear  to  give  to  their  results  an  interpretation 
more  or  less  physiological,  Brodmann  (9,  10)  in  particular  has 
expressed  this  stand  more  plainly  and  more  positively  than  most 
of  the  investigators.  He  has  written :  "Es  scheint  doch  naher  zu 
liegen  und  vom  histologischen  Standpunkte  aus  geradezu  gebo- 
ten,  spezifisch  differenten  Rindenzellen  auch  qualitativ  differente 
Funktionen  zuzuschreiben ;"  and  in  a  further  discussion  of  the 
matter:  "Die  spezifische  histologische  Differenzierung  von  Rin- 
denarealen  beweist  unwiderlegbar  deren  spezifische  funktionelle 
Differenzierung"  (9).  This  leads  directly  to  the  anatomical  divi- 
sion of  cerebral  function,  to  a  sort  of  phrenology,  and  to  an 
anatomy  of  mind  which  will  not  bear  criticism. 


THE  OCCIPITAL  LOBE 

The  gross  appearance  and  the  extent  of  the  occipital  lobe  may 
be  learned  from  the  text  books  of  anatomy  (61),  or  will  be  re- 
called by  a  glance  at  figs,  i  and  2.  The  lobe  comprises  about  one- 
eighth  of  the  superficial  part  of  the  cerebral  cortex.  On  the 
mesial  aspect  of  the  hemisphere  the  calcarine  fissure  is  included  in 
this  area,  and  its  upper  and  anterior  limits  are  roughly  fixed  by 
the  parieto-occipital  sulcus.  On  the  lateral  aspect  it  reaches  to 
the  transverse  occipital  fissure.  In  the  fresh  as  well  as  in  stained 
sections  of  part  of  this  region  there  can  be  seen  in  the  cortex 
without  the  aid  of  the  microscope  a  distinctly  lighter  streak,  ap- 
parently dividing  the  cortex  into  two  layers.  This  is  the  line  of 
Gennari  which,  both  macroscopically  and  microscopically,  gives 
to  this  area  an  appearance  very  different  from  all  other  parts  of 
the  cerebral  cortex. 

Further  examinations  of  the  cortex  by  histological  methods 
reveal  other  differences.  The  larger  region  is  found  to  have  two 
or  three  different  types  of  arrangements  of  cells  and  fibers,  so 
that  by  the  more  careful  methods  it  is  possible  to  distinguish  and 
to  differentiate  two  or  three  areas  of  anatomically  (histologic- 
ally)  distinct  types.  The  most  characteristic  of  these  areas  is  the 
one  in  which  the  line  of  Gennari  is  prominent,  an  area  which  may 
be  called  the  calcarine  area.  This  area  surrounds  the  calcarint 
fissure,  and  in  man  reaches  beyond  the  occipital  pole  toward  the 
lateral  aspect  of  the  cerebrum  for  only  a  very  short  distance. 
The  limits  of  this  area  have  been  accurately  determined  by  a 
number  of  investigators,  all  of  whom  report  essentially  the  same 
results.  The  structure  of  this  region  is  described  by  Campbell 
as  follows  (n,  p.  17)  :  "The  characters  which  distinguish  the 
calcarine  type  of  cell  lamination  are,  first,  the  almost  unique  layer 
of  large  stellate  cells  usurping  the  position  occupied  by  the  exter- 
nal layer  of  large  pyramidal  cells  in  other  regions ;  secondly,  the 
existence  of  pale-stained  zones  above  and  below  the  uncommonly 
well-marked  layer  of  stellate  cells,  the  upper  of  which  marks  the 
position  of  the  line  of  Gennari;  thirdly,  the  presence  in  the 
depths  of  the  cortex  of  the  layer  of  solitary  cells  of  Meynert, 
cells  which  differ  from  homonymous  cells  in  any  other  part  of 


4  SHEPHERD   IVORY  FRANZ 

the  brain."  The  remainder  of  the  occipital  lobe  is  considered 
by  Campbell  to  be  one  area,  while  Brodmann  has  been  able  to 
distinguish  two  separate  areas,  which  he  admits  are  closely  re- 
lated (10,  p.  228).  The  cortex  surrounding  the  calcarine  area, 


FIGS,  i  and  2.  The  human  cerebrum,  with  the  areal  differentiation  of  the 
occipital  lobe.  The  dotted  part  is  the  calarine  type,  and  the  parts  marked 
by  horizontal  lines  and  by  cross  hatching  are  the  remainder  of  the  so-called 
visual  cortex.  Adapted  from  Brodmann,  and  reduced. 

and  extending  1.5  to  2  cm.  beyond  it,  is  supposed  to  have  a  func- 
tion somewhat  similar  to  that  of  the  calcarine  area,  in  that  it  is 
intimately  related  to  the  calcarine  area,  and  has  been  correlated 


THE  OCCIPITAL  LOBE 


with  certain  clinical  findings  relating  to  vision.  To  this  region 
Campbell  gives  the  name  visuo-psychic  as  distinguished  from  the 
calcarine  which  is  called  visuo-sensory.2  The  structural  ap- 
pearance of  this  surrounding  area  is  somewhat  similar  to  that 
of  the  calcarine  area,  but  sufficiently  different  from  the  latter  to 
be  considered  distinct.  The  cortex  is  of  greater  depth,  the  plexi- 
form  and  small  and  medium-sized  pyramidal  cells  are  all  appre- 
ciably deeper,  but  the  latter  two  are  less  numerous;  the  large 
pyramidal  cells  are  mixed  with  the  other  cells  and  do  not  form 
a  layer  by  themselves;  the  layer  of  stellate  cells  has  an  appear- 
ance similar  to  that  in  the  calcarine  area,  and  the  other  cell  ele- 
ments are  not  divided  into  layers  as  in  the  calcarine  region. 

Figs,  i  and  2  illustrate  the  division  by  histological  methods  of 
the  occipital  cortex  in  man  by  Brodmann.     Here  is  shown  the 


FIGS.  3  and  4.  The  occipital  pole  of  the  human  cerebrum,  with  the  areal 
distributions  of  the  so-called  visuo-sensory  and  the  visuo-psychic  regions. 
The  dotted  portion  is  the  calcarine  type  of  cortex,  and  the  cross  hatched 
portion  is  the  visuo-psychic  area.  Adapted  from  Campbell.  3,  the  mesial 
aspect ;  4,  the  lateral  aspect. 

calcarine  area,  marked  by  large  dots,  surrounding  that  fissure, 
and  in  the  neighboring  regions  the  two  areas  closely  related  to 
the  calcarine  but  differing  from  the  latter  in  cell  and  fiber  struct- 
ure. The  two  areas,  as  has  been  indicated  above,  are  not  abso- 
lutely distinct  and  have  been  grouped  by  Brodmann  to  make  one 
area.  By  this  grouping  Brodmann  closely  approaches  the  divi- 
sions made  by  Campbell  (u),  by  Elliot  Smith  (69)  and  by 
Bolton  (8),  as  well  as  those  made  by  the  earlier  investigators. 

2  These  names  were  previously  used  by  Bolton. 


6  SHEPHERD   IVORY  FRANZ 

The  division  of  the  cortex  by  Campbell  is  given  in  figs.  3  and  4, 
which  should  be  compared  with  the  division  by  Brodmann  in 
figs,  i  and  2.  It  will  be  seen  that  the  total  extent  of  the  cortex 
supposedly  devoted  to  visual  function  is  approximately  the  same 
in  the  two  figures,  the  apparent  difference  being  accounted  for 
by  the  different  views  of  the  brain  which  the  two  investigators 
have  used  for  the  delineation  of  the  areas.  The  most  marked 
difference  between  the  areal  distributions  of  Campbell  and  Brod- 
mann is  the  larger  relative  size  of  the  calcarine  cortex  outlined 
by  Campbell.  The  surrounding  region  is,  however,  not  so  easily 
differentiated  from  the  remainder  of  the  brain  as  is  the  calcarine 
cortex,  and  the  variations  of  the  individual  observers  may  be 
due  to  actual  differences  in  material,  as  Bolton  (7)  suggests  in 
regard  to  another  matter.  Bolton  reports  that  in  an  examination 
of  brains  for  the  exact  localization  of  the  visual  cortex  he  found 
individual  differences  apart  from  the  age  and  the  visual  abilities 
of  the  people  whose  brains  he  examined,  and  he  remarks  that 
"as  such  differences  exist  in  a  projection  area,  it  is  possible  that 
more  marked  variations  will  occur  in  the  case  of  the  later  special- 
ized areas  of  different  brains"  (7,  p.  309). 

In  the  monkey  the  occipital  lobe  is  more  constant  and  more 
easily  mapped  out  by  fissures  than  in  the  human  brain.  It  may 
be  described  as  that  part  of  the  cortex  on  the  lateral  aspect  almost 
inclosed  by  the  parieto-occipital  and  the  inf.  occipital  fissures,  and 
as  the  part  on  the  mesial  aspect  which  surrounds  the  calcarine 
fissure,  bounded  above  by  the  parieto-occipital  fissure  and  below 
by  a  line  drawn  from  the  calcarine  fissure  to  the  inferior  occipi- 
tal. The  cortex  in  this  area  shows  types  of  arrangement  similar 
to  those  found  in  the  human  brain,  and  it  has  been  found  possi- 
ble to  map  the  region  into  at  least  two  distinct  areas,  the  so-called 
visuo-sensory  and  the  visuo-psychic.  Figs.  5  and  6  show  this 
division,  but  into  three  areas  corresponding  with  the  three 
divisions  of  the  human  brain  by  Brodmann.  It  will  be  seen  that 
the  calcarine  type  of  cortex  occupies  a  much  larger  area  than  in 
the  human  brain,  not  only  relatively  to  the  size  of  the  whole 
cortex,  but  also  absolutely  larger  than  the  same  type  in  man  if  we 
disregard  the  infolding  of  the  calcarine  fissure.  Brodmann  has 


THE  OCCIPITAL  LOBE 


6 


FIGS.  5  and  6.  Distribution  of  the  various  types  of  cortex  in  the  occipital 
lobe  of  the  monkey  (Cercopithecus).  Same  designations  for  the  areas  as 
in  figure  I.  Adapted  from  Brodmann,  and  reduced. 

not  illustrated  the  extent  of  this  area  in  the  Macacque  monkey, 
but  only  in  the  Cercopithecus,  the  brain  of  which  closely  resem- 
bles that  of  the  Macacque.  Mott  has  given  illustrations  of  the 
Macacque  brain  with  the  distribution  of  the  calcarine  type  of 
cortex,  which  are  here  reproduced  (figs.  7  and  8)  for  comparison 
with  that  of  the  distribution  in  the  Cercopithecus  by  Brodmann. 
The  findings  of  Mott  (50)  differ  very  much  from  those  of  Brod- 
mann in  the  allied  family.  He  does  not  illustrate  the  extension 
of  the  so-called  visuo-psychic  type  of  cortex  and  it  is,  therefore, 
impossible  to  make  a  full  comparison  with  the  findings  of  Brod- 
mann. It  may  be  said,  however,  that  the  examination  of  the  brains 
of  the  Rhesus  monkeys  used  in  the  present  work  has  shown  a 
distribution  of  the  calcarine  type  of  cortex  more  nearly  like  that 


8 


SHEPHERD   IVORY  FRANZ 


found  by   Broclmann  in  Cercopithecus  than  that  illustrated  by 
Mott  in  the  Rhesus.3 


FIGS.  7  and  8.  Illustrating  the  distribution  of  the  calcarine  type  of  cortex 
in  the  Macacque  monkey  (Macacus  Rhesus).  Adapted  from  Mott,  and 
reduced. 

From  the  resume  of  the  work  of  the  different  histologists  it 
will  be  seen  that  the  occipital  cortex  can  be  roughly  divided  into 
two  areas,  of  somewhat  different  structure,  and  that  one  of  these 
areas  is  very  definite.  The  anatomo-pathological  studies  indicate 
a  close  connection  between  the  occipital  lobes  and  the  eyes  and 
this  connection  is  admitted  for  the  calcarine  type  of  cortex  more 
generally  than  for  the  surrounding  regions.  In  the  next  section 
of  this  article,  we  shall  see  there  is  little  warrant  for  the  assump- 
tion that  the  cortex  surrounding  the  calcarine  type  of  cortex  has 
visuo-psychic  functions,  although  most  workers  in  this  field  be- 
lieve that  the  calcarine  cortex  is  concerned  with  visual  sensations. 

The  occipital  lobe  is  in  connection  with  the  external  geniculate 
bodies,  the  pulvinar  and  the  anterior  corpora  quadrigemina.4 

8  No  special  effort  was  made  to  mark  the  limits  of  the  other  areas  of  the 
occipital  cortex  and  a  definite  statement  of  their  extent  in  the  Rhesus 
monkey  can  not  be  made  at  present. 

4  For  the  description  of  the  relations  and  the  connections  between  the 
occipital  lobes  and  the  retinae,  see  especially  von  Monakow  (45,  47  and  48),. 
Dimmer  (13),  Knies  (38),  Moeli  (44),  and  Mott  (49). 


HISTORICAL  9 

THE    LOCALIZATION    OF    FUNCTION    IN    THE    OCCIPITAL    LOBE 

Movement.  Electrical  stimulation  of  the  occipital  cortex  re- 
sults in  movements  of  the  eyeballs  and  of  the  intrinsic  eye  mus-  / 
cles.  The  eyeball  movements  are  associated  movements.  Differ- 
ent observers  have  located  in  this  region  centers  for  a  number 'of 
movements,  and  have  demonstrated  a  functional  connection  be- 
tween this  region  and  the  precentral  cortex.  It  has  been  found 
that  the  eye  movements  occur  upon  stimulation  of  the  occipital 
lobes  even  after  the  frontal  cortex  has  been  destroyed,  and  that 
they  also  occur  upon  stimulation  of  the  frontal  cortex 
after  the  occipital  lobes  have  been  extirpated.  This  has  been  taken 
to  mean  that  there  are  independent  centers  for  the  movements  of 
the  eyes;  one  in  the  occipital  lobe,  the  other  in  the  cortex  an- 
terior to  the  central  fissure. 

Ferrier  (14)  reported  that  in  monkeys  stimulation  of  points 
on  the  angular  gyrus  produced  movements  of  the  eyes  "to  the 
opposite  side,  with  an  upward  and  downward  deviation,  accord- 
ing as  the  electrodes  are  placed"  anterior  or  posterior  to  the  paral- 
lel fissure.  He  has  also  noted  the  contraction  of  the  pupils  and 
the  tendency  to  closure  of  the  eyelids,  and  occasionally  an  asso- 
ciated movement  of  the  head  to  the  opposite  side.  Ferrier's  ob- 
servations have  not  been  confirmed  by  other  observers,  and 
Schafer  (62,  64)  and  others  assign  to  the  occipital  lobes  this 
motor  function.  Schafer  reports :  "If  the  electrodes  are  applied 
directly  to  the  upper  surface  of  the  occipital  lobe,  conjugate  devia- 
tion to  the  opposite  side  with  downward  direction  of  the  visual 
axes  is  extremely  well  marked,  and  it  is  also  produced  by  excita- 
tion of  the  upper  part  of  the  mesial  surface  of  that  lobe,  and 
of  the  quadrate  lobule  immediately  in  front  of  the  internal  par- 
ieto-occipital  fissure.  If,  on  the  other  hand,  the  posterior  ex- 
tremity of  the  occipital  lobe,  its  lower  or  tentorial  surface,  and 
the  posterior  and  lowermost  part  of  its  mesial  surface  be  stimu- 
lated, the  lateral  deviation  is  combined  with  an  upward  move- 
ment. In  both  cases  the  downward  or  upward  movement  may 
be  almost  uncomplicated  by  lateral  deviation;  this  depends  upon 
the  position  of  the  electrodes.  On  the  other  hand,  there  is  an 
intermediate  zone,  narrow  on  the  mesial  surface  of  the  lobe,  and 
broader  upon  the  outer  or  convex  surface,  excitation  of  which 


io  SHEPHERD   IVORY  FRANZ 

is  productive  of  simple  lateral  deviation.  All  the  effects  are 
strongest  upon  the  mesial  surface,  especially  toward  the  anterior 
limit  of  the  lobe ;  it  is  here  that  the  local  point  for  the  movements 
is  located."  On  the  assumption  that  the  eye  movements  resulting 
from  stimulation  of  the  occipital  lobes  are  due  to  something  akin 
to  sensations  Schafer  (64,  p.  5)  was  led  to  conclude  that  the 
occipital  lobe  has  the  following  physiological  connections :  "The 
whole  of  the  visual  area  of  one  hemisphere  is  connected  with 
corresponding  lateral  half  of  both  retinae.  The  upper  zone  of 
the  visual  area  of  one  hemisphere  is  connected  with  the  upper 
part  of  the  corresponding  lateral  half  of  both  retinae.  The  inter- 
mediate zone  of  the  visual  area  is  connected  with  the  middle  part 
of  the  corresponding  lateral  half  of  both  retinae."  Von  Bech- 
terew  (2)  has  located  only  three  centers  for  movement  of  the 
extrinsic  eye  muscles,  and  he  has  reported  that  eye  movements 
may  be  obtained  from  stimulation  of  the  parietal  lobe  as  well  as 
from  the  stimulation  of  the  occipital.  It  is  worthy  of  note  that 
Steiner  (70)  has  found  the  occipital  lobe  unresponsive  at  birth, 
although  at  this  time  the  stimulation  of  the  frontal  (pre-Rolan- 
dic)  cortex  results  in  eye  movements.  This  has  been  confirmed 
by  Berger.5 

Many  observers  have  recorded  movements  of  the  iris,  i.  e., 
pupillary  changes,  following  the  stimulation  of  the  occipital  lobes. 
Von  Bechterew  has  located  in  the  occipital  lobes  two  centers  for 
pupillary  movements,  a  contraction  center  in  the  middle  part  of 
the  occipital  lobe,  and  a  dilating  center  slightly  inwards  from 
the  contraction  center.  These  results  or  similar  ones  have  been 
found  by  other  observers,  and  they  are  partly  confirmed  by  the 
observations  on  man  when  there  is  disease  or  destruction  of  the 
occipital  cortex.6 

The  observation  of  Schafer  (66,  p.  750)  on  the  latent  periods 
of  the  movements  from  stimulation  of  the  occipital  lobe  and  of 
the  precentral  cortex  are  of  primary  importance,  and  have  often 

"See  also  Schafer  (62),  Gerwer  (22),  Mott  and  Schafer  (51)  and 
Obregia  (57). 

6  On  the  pupillary  changes  see  also  the  following  articles :  v.  Bechterew 
(2,  3)  ;  Parsons  (59)  ;  Mislawsky  (43)  ;  and  also  Alamagny  (i)  ;  zur  Verth 
(72);  Bernheimer  (6);  Leyden  (39). 


HISTORICAL  ii 

been  overlooked  by  other  investigators.  He  has  carefully  timed 
the  movements  and  finds  that  the  latent  period  for  movements 
from  occipital  lobe  stimulation  is  much  longer  than  that  from 
the  stimulation  of  the  Rolandic  area.  That  this  lengthening  of 
the  time  is  not  due  to  the  passage  of  the  impulse  to  the  frontal 
lobe,  i.  e.,  to  the  motor  cortex,  and  thence  to  the  muscles  is  shown 
by  the  fact  that  the  movements  from  stimulation  of  the  occipitals 
may  be  obtained  after  the  frontal  lobes  have  been  excised.  We 
are,  therefore,  compelled  to  conclude  that  the  cells  in  the  occipital 
lobes  have  a  more  direct  connection  than  that  through  the  motor 
cortex,  although  it  is  apparent  from  the  results  of  Schafer's  work 
that  there  are  more  intercalated  cells  in  the  chain  from  the  occipi- 
tal lobes  to  the  eye  than  from  the  pre-Rolandic  cortex  to  the  same 
muscles. 

Sensation.  It  was  known  for  a  long  time  that  destruction  or 
injury  of  parts  of  the  cerebrum  caused  visual  defects  or  disturb- 
ances, but  the  recognition  of  a  localized  center  or  centers  for 
visual  sensation  and  perception  has  been  largely  due  to  the  results 
of  experiments  on  animals.  In  the  hands  of  different  observers 
the  method  of  extirpation  has  led  to  somewhat  discordant  re- 
sults, and  to  opposing  conclusions.  The  controversies  regarding 
the  functions  of  the  occipital  lobes  will  not  detain  us  here,  but 
although  they  apparently  did  not  change  the  opinions  of  those 
who  took  leading  parts  therein  they  have  left  us  many  observa- 
tions of  value. 

Extirpation  of  certain  cortical  areas  in  the  dog's  brain  led 
Munk  to  the  conclusion  that  in  this  animal  there  is  a  center  (des- 
ignated by  him  as  Ai)  for  visual  perception  and  that  the  sur- 
rounding more  extensive  region  was  a  subsidiary  visual  center 
which  could  be  used  when  the  primary  center  was  injured  or  des- 
troyed. Munk  (52-56)  furthermore  attempted  a  more  careful 
localization  and  attributed  to  parts  of  the  center  more  definite 
functions.  The  conclusions  of  Munk  were  strongly  combatted 
by  Goltz  who  at  first  denied  there  was  any  localization  in  the 
cortex  of  the  brain,  but  who  later  admitted  that  a  certain  amount 
of  localization  was  possible,  and  in  fact  was  indicated  by  the 
results  of  the  experimental  investigations.  The  position  taken 


12  SHEPHERD   IVORY  FRANZ 

by  Goltz  (23-25)  in  regard  to  localization  of  vision  was  that 
although  a  visual  defect,  which  he  did  not  deny,  might  be  pro- 
duced by  the  ablation  of  part  of  the  cerebral  cortex,  the  defect 
was  not  due  to  the  extirpation  of  the  cortical  cells  concerned  with 
the  visual  processes,  but  to  a  general  effect  and  might  be  pro- 
duced by  the  extirpation  of  parts  of  the  brain  other  than  that 
assigned  the  visual  function  by  Munk.  Regarding  this  he  has 
written :  (23)  "Indem  ich  also  auf  Grund  meiner  neureren  Erfah- 
rungen  einen  grosseren  Einfluss  des  Hinterhirns  auf  das  Sehver- 
mogen  fur  festgestellt  erachte,  kommt  es  mir  dabei  nicht  in  den 
Sinn,  etwa  eine  begrenzte  Sehsphare  zuzugeben,  wie  sie  Ferrier, 
Munk  und  Luciani  konstruiert  haben."  This  admission  of  the 
possibility  of  localization  is  much  the  same  as  that  of  Loeb 
(40-42)  who  investigated  the  so-called  visual  cortex  at  a  later 
date,  and  who  has  taken  a  stand  much  like  that  of  Goltz.  Loeb 
asserts  that  the  visual  disturbance  following  operations  upon 
the  occipital  lobes  which  is  temporary  in  character  is  due  to  a 
lowering  of  the  irritability  of  the  retina-cerebral  cortex  mechan- 
ism. The  differences  between  the  Munk  and  Goltz  school  does 
not,  however,  disappear  even  if  we  consider  that  the  Goltz  and 
Loeb  explanation  of  the  latter  be  correct  for  the  symptoms  that 
are  temporary.  Part  of  the  difference  between  the  explanations 
of  Munk  and  Goltz  rests,  as  von  Monakow  has  shown,  upon 
different  standpoints  in  the  collection  of  the  data.  Goltz  has 
used  as  evidences  of  the  presence  of  visual  sensations  the  move- 
ments of  the  eyes  and  of  the  related  parts  when  the  eyes  are 
stimulated  by  light,  but  there  is  no  reason  to  believe  that  these 
reactions  are  more  than  reflex  in  character,  and  there  is  good 
reason  to  believe  that  they  do  not  depend  entirely  upon  the  activi- 
ty of  the  cerebral  cortex.  It  would  be  equally  correct  to  say 
that  there  was  no  localization  of  movement  or  of  the  skin  sensa- 
tions because  it  is  possible  to  get  reflexes  of  the  leg  after  there 
has  been  complete  separation  of  the  spinal  cord  from  the  cere- 
brum. Loeb  does  admit,'  however,  that  the  destruction  of  the 
occipital  lobe  in  man  is  followed  by  a  blindness,  which  he  believes 
is  due  to  a  loss  of  irritability  on  one  side  of  each  retina,  but  he 
explains  the  results  in  dogs  to  be  not  a  loss  but  only  a  decrease 


HISTORICAL  13 

in  irritability  in  that  organ.7  He  furthermore  asserts  that, 
with  Goltz,  he  believes  the  associative  memory  of  animals  de- 
prived of  their  occipital  lobes  does  not  differ  from  that  they  had 
previous  to  the  operation.  The  main  difference  between  Goltz 
and  Loeb  and  the  followers  of  Munk,  Hitzig,  and  others,  is  in 
the  conception  of  the  relation  of  the  brain  to  mental  processes. 
The  former  object  to  the  interpretation  that  extirpations  of  or 
injury  to  parts  of  the  brain  cause  psychical  disturbances,  while 
Ferrier,  Munk,  Hitzig,  and  other  investigators  interpret  the  de- 
fects to  be  psychical.  From  the  standpoint  of  localization,  which 
apparently  all  admit  in  some  form,  the  important  question  is  not 
concerning  the  presence  or  absence  of  certain  psychical  disturb- 
ances but  the  definite  or  indefinite  restriction  of  certain  functions 
to  certain  areas.  There  can  be  no  doubt  that  in  man  certain 
cerebral  destructions  produce  certain  effects  of  the  nature  of  loss 
of  associations,  e.  g.,  those  of  speech,  and  the  clinicians  still  debate 
whether  or  not  these  losses  mean  mental  deterioration.  Whether 
or  not  the  disturbances  are  to  be  interpreted  as  psychical  will 
depend  upon  the  connotation  of  the  word  psychical. 

The  conclusions  of  Munk  were  supported  by  von  Monakow 
(46)  both  from  the  results  of  personal  experiments  and  from 
the  examination  of  the  brains  of  animals  upon  which  Munk  had 
operated,  von  Monakow,  however,  believes  the  visual  area  is  not 
as  small  as  it  was  pictured  by  Munk,  and  considers  that,  in  dogs 
at  least,  it  extends  anteriorly  beyond  the  limits  assigned  by  Munk. 

The  conditions  reported  by  Hitzig  (30-34)  following  removal 
of  parts  of  the  occipital  lobes  in  dogs  was  that  of  crossed  am- 
blyopia.  This  is  unlike  the  results  of  other  investigators,  who 
have  reported  a  condition  of  hemianopia  (for  the  opposite  visual 
field)  following  the  extirpation  of  cortical  regions  in  both  dogs 
and  monkeys.  Hitzig  had  also  been  led  to  conclude  that  a  similar 
condition  may  follow  lesions  of  the  anterior  part  of  the  brain, 
but  these  results  have  not  been  confirmed  by  independent  investi- 
gators. As  an  explanation  of  Hitzig's  conclusions  it  has  been 
pointed  out  that  the  visual  defect  in  the  dog  following  the  extir- 

7  Why  he  has  selected  the  eye  in  this  connection  is  not  made  clear,  for  it 
would  seem  that  the  explanation  should  be  made  in  regard  to  the  central 
nervous  structures. 


I4  SHEPHERD   IVORY  FRANZ 

pation  of  one  occipital  lobe  is  blindness,  not  for  the  opposite  eye, 
but  for  objects  in  the  opposite  field  of  vision,  which  on  account 
of  the  large  number  of  the  optic  fibers  crossing  at  the  chiasm  is 
more  marked  (i.  e.,  includes  more  than  half  of  the  visual  field) 
in  the  opposite  eye  in  the  dog.  Perimetric  examinations  of  ani- 
mals have  shown  that  from  two-thirds  to  three-quarters  of  one 
retina  in  the  dog  is  connected  with  the  homonymous  occipital 
lobe.  The  conclusions  of  Hitzig  are,  therefore,  taken  to  indicate 
that  on  account  of  the  involvement  of  such  a  proportion  of  the 
retina  of  the  one  eye  by  an  unilateral  occipital  lesion  the  exact 
nature  of  the  defect  was  not  discovered,  i.  e.,  there  was  retention 
of  vision  for  only  about  one-quarter  of  the  field  and  the  appear- 
ance was  that  of  a  complete  blindness  for  the  whole  field  of  that 
eye. 

Using  monkeys  as  subjects,  Ferrier  localized  the  visual  area 
at  first  in  the  angular  gyrus,  but  later  concluded  that  the  occipital 
lobe  was  used  in  connection  with  the  angular  gyrus,  and  called 
the  area  the  "occipito-angular"  area.  The  later  conclusions  of 
Ferrier  were  due  to  the  criticism  of  his  early  work  by  Schafer 
and  others,  and  to  the  fact  that  he  repeated  the  work  using  some- 
what different  methods.  His  early  experiments  were  performed 
without  aseptic  precautions,  and  it  is  this  condition  and  its  result- 
ant consequences  (e.  g.,  the  secondary  extension  of  the  injury  by 
infection,  etc.,)  which  Ferrier  uses  to  explain  his  first  results 
and  conclusions.  In  the  later  localization  work  by  Ferrier  (14, 
p.  268-305)  the  angular  gyrus  is  given  a  prominent  place  and 
he  reports  that  the  occipital  lobes  may  be  cut  away  alone  without  l 
appreciable  impairment  of  vision.  The  visual  defect  reported  by 
Ferrier  ( 14,  p.  273)  was  that  of  amblyopia.  Many  of  the  animals 
operated  upon  by  Ferrier  showed  a  blindness  which  persisted 
for  only  a  few  hours.  This  has  been  urged  by  others  as  a  criti- 
cism of  Ferrier's  work  and  conclusions,  for  it  has  been  said  that 
the  observations  taken  so  soon  after  the  completion  of  the  opera- 
tion do  not  warrant  the  conclusion  of  blindness.  Although  Fer- 
rier rightly  retorts  that  the  "period  of  reliable  observation  is  not 
to  be  measured  by  the  mere  time  that  has  elapsed  since  the  opera- 
tion, for  the  period  of  recovery  is  most  variable,  many  animals 
being  up  and  active  almost  before  their  wounds  have  been 


HISTORICAL  15 

dressed,"  it  does  appear  to  stretch  a  point  to  conclude  that  the 
blindness  may  remain  for  only  a  few  hours  and  then  entirely 
disappear.  In  reply  to  Schafer,  the  citation  of  cases  from  his 
work  in  1884  is  not  convincing  in  regard  to  the  part  played  by 
the  angular  gyrus  in  visual  perception  or  sensations  (15). 

Following  are  abstracts  of  several  cases  cited  by  him  in  the 
discussion  with  Schafer :  In  one  monkey  the  left  angular  gyrus 
was  cauterized.  The  left  eye  was  secured  so  that  the  animal 
could  not  use  it  for  vision.  A  half  hour  after  the  operation  the 
animal  was  apparently  "wide  awake  but  would  not  move  unless 
touched";  it  sprawled  on  the  floor  and  knocked  against  obstacles; 
an  hour  later  it  bounded  away  when  it  was  touched  and  ran 
against  the  leg  of  a  table,  but  did  not  show  signs  of  perception 
when  it  was  approached  cautiously  without  noise ;  on  the  follow- 
ing day  "no  'defect  of  vision,  amblyopic  or  hemiopic,  could  be 
detected."  In  regard  to  the  effects  of  similar  lesions  on  other 
animals  he  says :  "Similar  results  were  obtained  in  many  other 
instances,  and  if  in  some  they  were  even  more  transient,  this 
may  have  been  due  to  less  extensive  destruction  or  perhaps  dif- 
ferences in  animals  as  to  the  relative  importance  of  this  region 
in  the  ordinary  exercise  of  their  visual  function."  Three  cases 
cited  by  him  are  to  be  compared  with  the  results  in  the  present 
work.  In  these  three  animals  the  occipital  lobes  were  destroyed 
or  severed  with  great  care  so  that  the  angular  gyri  were  not  in- 
jured. In  one  the  occipital  lobes  were  exposed  and  the  surfaces 
were  "destroyed  by  cautery,  which  was  also  passed  deeply  into 
the  interior  of  the  lobes  so  as  to  cause  as  much  disorganization 
as  possible.  Care  was  taken  not  to  injure  the  angular  gyrus." 
About  forty  minutes  after  the  operation  the  animal  began  to 
move  but  staggered  a  good  deal ;  its  eyes  were  open  and  the  pupils 
were  dilated.  An  hour  and  a  half  later  there  was  "emphatic 
evidence  of  sight ;  ran  away  as  I  approached  it,  carefully  avoiding 
obstacles"  ;  it  entered  its  cage,  and  avoided  a  cat  that  had  taken  up 
its  quarters  there;  "tried  to  escape  my  hand  when  I  offered  to 
lay  hold  of  it,  but  picked  up  a  raisin  which  I  had  left  on  the 
perch."  In  a  second  animal  the  occipital  lobes  were  severed  "by 
a  perpendicular  section  with  hot  wires  about  a  quarter  of  an  inch 
posterior  to  the  parieto-occipital  fissure,  so  as  to  avoid  all  inter- 


16  SHEPHERD   IVORY  FRANZ 

ference  with  the  angular  gyrus;"  in  twenty-five  minutes,  it  was 
observed  that  the  animal  "can  see  quite  as  well,  as  it  avoids  ob- 
stacles, and  when  removed,  regains  its  position  by  the  fire."  In 
a  third  animal  "both  occipital  lobes  were  severed  with  a  galvanic 
cautery  and  scooped  out  bodily;  the  line  of  incision  in  both  cases 
passed  between  the  anterior  extremity  of  the  first  occipital  and 
the  parieto-occipital  sulcus;"  in  half  an  hour  the  animal  sat  up 
and  wanted  to  move  about ;  for  two  hours  there  were  no  definite 
tests  of  vision,  but  at  the  end  of  that  time  "a  piece  of  apple  was 
thrown  into  the  cage,  and  though  it  fell  a  full  arm's  length  away, 
the  animal,  without  the  slightest  hesitation  or  want  of  precision, 
put  forth  its  left  hand,  picked  it  up  and  ate." 

Ferrier  explains  the  results  of  Schafer  and  of  Munk  on  the 
ground  that  both  of  these  investigators  cut  away  more  than  the 
occipital  lobes  and  that  in  their  experiments  the  angular  gyri  were 
injured.  The  greatest  difference,  however,  between  the  conclu- 
sions of  Ferrier  and  Schafer  is  that  the  latter  believes  the  blind- 
ness is  of  the  nature  of  an  hemianopsia.  The  results  obtained  by 
Schafer,  especially  those  in  conjunction  with  Sanger  Brown,  are 
apparently  convincing  not  only  in  regard  to  the  participation  of 
the  occipitals  in  vision,  but  also  in  regard  to  the  character  of  the 
defect  following  lesions  in  these  regions  (67).  Schafer  (63,  65) 
not  only  obtained  results  on  the  occipitals  opposed  to  those  of 
Ferrier  but  has  failed  to  obtain  the  positive  results  on  the  angular 
gyri  reported  by  Ferrier  to  be  constant.  In  fact,  Schafer  has 
shown  that  the  angular  gyri  may  be  removed  without  interfering 
with  vision  in  the  least,  but  that  when  these  parts  are  removed 
and  the  underlying  fibers  (going  to  the  occipital  lobes)  are  in- 
jured, some  visual  disturbances  are  to  be  noticed.  Some  of 
Schafer's  results  are  particularly  instructive.  One  animal  upon 
which  he  operated,  extirpating  the  angular  gyri  on  both  sides, 
showed  no  loss  of  vision,  no  defect  of  movement  of  the  eyes,  and 
no  anesthesia  of  the  conjunctiva  or  the  cornea,  and  although  this 
animal  was  kept  alive  for  several  months,  no  disturbance  of  the 
eyes,  visual  or  otherwise,  was  found.  In  this  connection  Schafer 
concludes :  "A  single  well  marked  negative  case  like  this  is  con- 
clusive against  the  idea  that  in  the  monkey  cerebral  visual  per- 
ceptions are  localized  in  the  angular  gyri"  (63,  p.  365).  On  the 


HISTORICAL  17 

other  hand  the  positive  results  following  extirpations  of  the 
occipital  lobes  are  worthy  of  note.  One  animal,  the  left  occipital 
of  which  was  completely  removed  showed  a  bilateral  homonymous 
hemianopsia,  persisting  for  the  whole  time  the  animal  remained 
alive  (eight  months)  (63,  p.  367).  Another  monkey  from 
which  both  occipitals  were  removed  showed  a  "total  and  persis- 
tent blindness.  The  animal  could  only  find  food  by  groping  and 
smelling.  Brought  into  a  strange  place,  it  ran  against  every 
obstacle.  Placed  in  a  dark  room  and  with  a  light  flashed  upon 
it,  no  signs  of  perception  were  given.  Hearing  was  very  acute 
and  all  other  senses  besides  vision  were  unimpaired"  (63,  p. 
368-9).  This  animal  was  clinically  in  the  same  condition  as  a 
monkey  observed  by  Ferrier  and  Yeo,  from  the  brain  of  which 
they  removed  both  occipitals  and  both  angular  gyri.  Other  cases 
were  cited  which  confirm  this  general  conclusion  of  the  non-par- 
ticipation of  the  angular  gyri  in  the  same  sensory  processes.  In 
conclusion  Schafer  says  that  for  complete  blindness  the  "removal 
of  the  lobe  must  be  complete  and  when  a  small  portion  of  one  of 
the  lobes  is  left,  although  blindness  is  not  complete,  yet  the  limit 
of  the  visual  field  of  the  retinae  may  be  greatly  restricted"  (63,  p. 

370). 

Schafer  sums  up  the  differences  between  him  and  Ferrier  as 
f ollow,c ;  "The  chief  points  at  issue  are  ( I )  the  connection  of 
the  angular  gyrus  with  central  vision  of  the  opposite  eye;  (2) 
the  relative  importance  of  the  occipital  lobe.  According  to  Dr. 
Ferriers  experiments,  decorticisation  of  the  angular  gyrus  of 
one  side  produces  blindness  of  the  opposite  eye  (amblyopia)  ;  of 
both  sides  produces  blindness  of  both  eyes.  According  to  our 
experiments,  decorticisation  of  the  angular  gyrus  of  one  or  both 
sides  is  not  necessarily  followed  by  any  visual  defects  perceptible 
to  our  means  of  investigation  in  animals;  but  complete  eradica- 
tion of  the  gyrus  produces  hemiqpia  (not  amblyopia),  which  is 
temporary  only.  According  to  Dr.  Ferrier's  experiments,  de- 
struction of  one  or  both  occipital  lobes  alone  produces  no  appre- 
ciable effect  whatever  on  vision.  According  to  our  experiments — • 
which  are  merely  confirmatory  of  those  of  Munk — removal  of 
the  occipital  lobe  only,  without  the  angular  gyrus,  produces  per- 
manent hemiopia;  of  both  occipital  lobes,  blindness  of  both  eyes 


i8  SHEPHERD   IVORY   FRANZ 

which  is  also  permanent  and,xso  far  as  we  were  able  to  judge, 
complete"  (65,  pp.  158-9).  Schafer  admits  the  possibility  that 
the  visual  area  does  extend  beyond  the  limits  of  the  occipital  lobe 
and  asserts  that  the  cortex  undoubtedly  extends  somewhat  anter- 
iorly beyond  what  is  regarded  the  limits  of  the  occipital  lobe,  es- 
pecially on  the  under  surface  (and  perhaps  also  the  mesial 
surface). 

The  conclusions  of  Munk,  Goltz  and  Hitzig,  which  were  drawn 
from  observation  of  dogs  deprived  of  parts  of  the  cerebrum,  can 
not  be  applied  directly  to  man,  whose  brain  it  has  been  the  object 
to  understand  by  the  experiments  upon  animals.  On  the  other 
hand,  the  results  of  Ferrier  and  of  Schafer  are  almost  directly 
applicable  to  the  brain  of  man,  but  in  addition  to  the  experimental 
results  on  animals  there  are  numerous  clinical  observations  on 
man  of  the  visual  and  other  sensory  conditions  following  de- 
struction of  parts  of  the  brain,  and  the  results  of  these  observa- 
tions are  of  primary  importance.  Chief  among  the  results  that 
have  been  reported  are  those  of  Henschen  (27,  28).  This 
author  examined  all  the  available  accounts  of  reported  cases  of 
blindness  following  lesions  of  the  brain,  and  contributed  observa- 
tions of  personal  cases.  From  the  consideration  of  the  clinical 
accounts  and  of  the  patholbgico-anatomical  examinations  he  con- 
cludes that  the  visual  center  is  limited  to  the  cortex  of  the  calcar- 
ine  fissure,  and  that  the  centers  for  light  and  color  coincide.  He 
furthermore  defined  an  area,  in  the  anterior  part  of  the  calcarine 
fissure,  to  which  he  assigned  a  connection  with  the  macula  lutea, 
and  disputed  the  conclusions  of  others  who  located  the  macular 
center  in  the  cuneus.  Regarding  the  lateral  surface  of  the  occipi- 
tal lobes  and  the  cortex  of  the  angular  gyrus,  he  says  "I  have  not 
found  documents  which  prove  there  exists  a  projection  in  this 
part,  and  a  lesion  of  this  part  does  not  cause  blindness"  (28). 
This  part  of  the  cortex  is,  however,  admitted  by  him  to  have 
something  to  do  with  vision  and  this  fact  leads  to  the  conclusion 
that  there  are  two  areas :  one  restricted,  in  which  there  is  a  "pro- 
jection of  impressions,"  while  the  other,  extracalcarine  area,  does 
not  receive  the  impulses  directly,  and  is  more  extensive.  The 
calcarine  area  is  conceived  to  be  a  sort  of  brain  retina  while  the 
extra-calcarine  area  is  supposed  to  have  perceptive  functions. 


HISTORICAL  19 

Vialet  (73)  using  similar  material  concluded  that  the  visual 
center  extended  beyond  the  calcarine  fissure,  including  the  cuneus, 
the  lingual  and  the  fusiform  lobules,  and  part  of  the  occipital 
pole.  He  concluded  that  lesions  of  these  parts  separately  ma\ 
be  accompanied  by  hemianopsia,  but  Henschen  has  analyzed  the 
cases  of  Vialet  and  has  assured  himself  that  the  results  obtained 
by  the  latter  are  in  harmony  with  his  own  hypothesis.  Against 
the  hypothesis  of  Henschen,  von  Monakow  has  brought  forth  the 
fact  that  in  cases  of  early  blindness  with  total  destruction  of  the 
optic  nerve,  where  we  expect  to  find  the  cortex  wasted  in  the 
corresponding  brain  areas,  the  principal  atrophy  is  to  be  observed 
over  the  convexity  of  the  occipital  lobes  as  well  as  along  the  cal- 
carine fissure.  The  conclusion  of  von  Monakow  has  recently 
been  supported  by  Wehrli  (77)  who  has  examined  histologicallv 
the  brains  in  cases  of  blindness.  He  supports  the  view  that  the 
fibers  from  the  macula  lutea  spread  over  a  wide  area  at  the 
occipital  pole,  and  that  the  visual  area  is  widely  distributed  and 
not  to  be  limited  to  the  area  surrounding  the  calcarine  fissure,  not 
even  to  the  part  of  the  cortex  with  the  cell  lamination  known  as 
the  calcarine  type.  He  claims,  furthermore,  that  purely  cortical 
lesions  causing  hemianopsia  have  never  been  observed. 

There  aie  many  cases  reported  clinically  which  seem  to  indi- 
cate that  the  localization  of  visual  processes  is  not  as  limited  as 
Henschen  believes,  but  it  must  be  said  that  the  observations  have 
often  been  poorly  made,  not  only  clinically  but  also  pathologically, 
and  it  is  difficult  to  estimate  the  value  of  the  individual  contribu- 
tions. Of  the  negative  results  with  the  experimental  method,  tht 
work  of  Vitzou  (74-76)  is  of  interest.  He  extirpated  parts  of 
the  occipital  lobes  and  of  the  angular  gyri  and  found  the  animals 
lost  their  visual  ability  immediately  after  the  operation,  but  recov- 
ered it  to  a  great  extent  during  the  time  they  lived.  In  one  animal 
he  extirpated  the  occipital  lobes  but  preserved  the  angular  gyri. 
Although  this  animal  was  blind  after  the  operation,  this  condition 
ameliorated  in  a  month  and  a  half,  and  after  twenty-one  months 
the  animal  was  able  to  recognize  its  cage  and  people.  'A  second 
monkey,  in  (which  both  angular  gyri  and  both  occipitals  were  ex- 
tirpated, was  completely  blind  for  about  two  months  but  follow- 
ing this  period  it  began  to  recognize  objects  and  persons.  In  a 


20  SHEPHERD   IVORY  FRANZ 

third  monkey,  both  occipitals  and  parts  of  both  angular  gyri  were 
extirpated.  This  operation  resulted  in  complete  blindness  for 
about  two  months,  but  at  the  time  the  report  was  made,  about  one 
year  and  three  quarters  after  the  operation,  the  monkey  recog- 
nized objects  and  people.  This  animal  is  reported  to  have  been 
able  to  see  better  than  either  of  the  two  previously  described  ani- 
mals. In  a  fourth  monkey  both  occipitals  and  the  posterior  parts 
of  both  angular  gyri  were  removed,  causing  complete  blindness, 
which  was  much  improved  at  the  time  of  the  report,  twenty-one 
months  after  the  operation. 

Somewhat  similar  negative  results  have  been  reported  by 
Panici  (58)  from  the  laboratory  of  Luciani.  The  conditions  of 
three  monkeys  are  reported,  in  which  various  operations  were 
performed.  In  one  animal  the  decortication  of  the  posterior 
segment  of  the  right  calcarine  fissure  produced  a  bilateral 
homonymous  psychical  hemianopsia  which  persisted  for  only  two 
days.  In  a  second  monkey  Panici  first  extirpated  the  posterior 
part  of  the  left  cuneus.  This  resulted  in  no  defect  of  vision,  but 
following  a  second  operation,  in  which  additional  cortex  of  the 
left  occipital  lobe  was  extirpated,  there  was  found  a  condition 
similar  to  that  in  monkey  I,  but  which  lasted  only  three  days. 
Seven  days  after  the  second  operation,  Panici  extirpated  the 
whole  left  occipital  lobe,  and  found  a  bilateral  homonymous  psy- 
chical blindness  for  about  a  month,  which  condition  gave  place 
to  an  amblyopia.  A  month  later  he  extirpated  the  whole  of  the 
right  occipital  lobe,  and  found  this  to  result  in  a  right  psychical 
hemianopsia  for  about  a  month,  after  which  time  the  animal 
began  to  react  to  food,  but  remained  indifferent  to  gestures  and 
to  a  mirror,  but  with  a  corresponding  amblyopia.  At  the  first 
operation  on  a  third  monkey  the  internal  portions  of  the  right 
and  left  cuneate  lobes  were  extirpated,  and  a  week  later  this  was 
followed  by  a  more  extensive  extirpation.  Neither  of  these  oper- 
ations appeared  to  have  any  effect  upon  the  visual  ability  of  the 
animal,  but  after  the  third  operation,  three  weeks  after  the  second, 
the  complete  excision  of  the  left  occipital  was  accompanied  by  a 
bilateral  homonymous  psychical  hemianopsia,  which  continued 
for  about  a  year.  Twelve  days  after  this  operation  the  right 
occipital  lobe  was  completely  severed,  which  produced  a  complete 


HISTORICAL  21 

psychical  blindness  for  one  year.  Thirteen  months  later  a  final 
operation  on  the  left  produced  complete  blindness  in  the  right 
visual  field,  and  three  and  a  half  months  subsequent  to  the  opera- 
tion on  the  left  the  right  hemisphere  was  destroyed  up  to  the  fis- 
sure of  Rolando.  After  the  extensive  destruction  just  noted  the 
animal  became  blind  in  both  eyes,  over  the  whole  field. 

These  results  of  Panici  are  of  very  great  interest  for  they 
show  how  much  of  the  brain  must  be  destroyed  to  produce  a 
complete  blindness,  and  also  because  they  show  how  transient 
some  of  the  visual  defects  may  be.  It  will  be  seen  in  the  experi- 
mental part  of  this  article  how  closely  some  of  the  results  of 
Panici  resemble  those  observed  by  me. 

By  the  method  of  recording  electromotor  changes  in  the  brain, 
Danielewski  (12)  and  Gotch  and  Horsley  (26)  found  the  occipi- 
tal lobes  responded  to  stimulation  of  the  retina  and  the  optic 
nerve. 

After  considering  the  various  facts  Schafer  (66)  has  summed 
up  regarding  the  occipital  lobes  in  man  as  follows:  "There  is 
abundant  clinical  evidence  to  show :  That  lesions  of  the  occipital 
lobe  produce  disturbances  of  vision  which  are  invariably  of  a 
hemiopic  character.  That  lesions  of  the  mesial  surface  of  the 
lobe  in  the  immediate  neighborhood  of  the  calcarine  fissure  are 
those  which  for  their  size  produce  the  most  serious  visual  disturb- 
ances. On  the  other  hand,  lesions  of  parts  near  to  but  not  involv- 
ing these  parts  of  the  occipital  lobe  have  not  infrequently  been 
associated  with  defective  appreciation  of  visual  objects  and  par- 
ticularly with  word  blindness.  Perimetric  observations  in  man 
show  that  in  cases  of  hemiopia,  produced  by  lesions  of  the  cor- 
tex (of  one  hemisphere),  the  line  of  demarcation  between  the 
blind  and  functional  parts  of  the  retina  usually  passes,  not 
through  the  middle  of  the  fovea,  but  on  the  homonymous  side, 
in  other  words,  the  fovea  is  not  involved  in  the  hemiopic  condi- 
tion." These,  and  the  observations  of  animals  following  experi- 
mental lesions  have  led  him  to  the  following  conclusions:  "The 
whole  of  the  visual  area  of  one  hemisphere  is  connected  with  the 
corresponding  lateral  half  of  both  retinae.  The  upper  zone  of 
the  visual  area  of  one  hemisphere  is  connected  with  the  upper 
zone  of  the  corresponding  lateral  half  of  both  retinae.  The  lower 


22  SHEPHERD   IVORY  FRANZ 

zone  of  the  visual  area  of  one  hemisphere  is  connected  with  the 
lower  zone  of  the  corresponding  lateral  half  of  both  retinae.  The 
intermediate  zone  of  the  visual  area  is  connected  with  the  middle 
zone  of  the  corresponding  lateral  half  of  both  retinae.  The 
focal  point  of  the  visual  area,  which  is  placed  on  the  anterior  part 
of  the  mesial  surface  of  the  occipital  lobe,  is  connected  with 
rather  more  than  the  corresponding  half  of  the  macula  lutea  of 
each  retinae."  With  these  conclusions  von  Monakow  (47)  is 
not  in  complete  accord,  although  he  considers  the  visual  areas  to 
be  rather  widely  spread,  and  not  be  located  in  a  small  area.8 
He  believes  the  visual  area  for  sensations  extends  beyond  the 
calcarine  area,  and  includes  the  lateral  part  of  the  occipital  lobes, 
the  cuneus,  the  lingual  lobule  and  the  gyrus  descendens.  More 
than  this,  von  Monakow  admits  that  the  subcortical  parts  may 
have  something  to  do  with  visual  sensations  (as  mental  phe- 
nomena), and  if  this  be  so,  it  would  explain  many  of  the  appar- 
ently discordant  observations  and  conclusions  of  experimenters 
and  clinicians. 

Throughout  the  previous  discussion  the  psychological  conclu- 
sions regarding  the  experiments  upon  animals  and  the  observa- 
tions of  man  have  been  reported  as  if  they  were  of  about  the 
same  character.  This  is  not  so,  for  we  find  the  results  have  been 
interpreted  to  mean  that  the  occipital  lobes  are  the  sensory  receiv- 
ing stations,  or,  on  the  other  hand,  that  these  portions  of  the 
brain  are  the  places  in  which  the  visual  associations  (physiologi- 
cal and  psychological)  take  place.  From  the  first  point  of  view 
the  visual  disturbances  are  considered  to  be  inabilities  to  see, 
from  the  second  they  are  conceived  to  be  inabilities  to  perceive. 
This  is  the  main  point  of  difference  between  the  adherents  of 
Goltz  and  those  of  Munk.  With  the  methods  used  by  these  inves- 
tigators a  solution  of  the  problem  is  not  possible,  and  the  results 
-which  have  been  reported  to  us  may  be  interpreted  in  either  way. 

Perceptions,  etc.  Regarding  the  psychic  or  higher  intellectual 
functions  of  the  occipital  lobes  little  need  be  said.  In  an  area 
close  to  the  occipitals  some  have  located  the  visual  speech  func- 

8  "Diese  und  andere  Beobachtungen  batten  mich  zu  der  Annahme  gefiihrt, 
dass  die  Stelle  des  deutlichsten  Sehens  iiberhaupt  nicht  in  einer  engen  cor- 
ticalen  Zone  reprasentiart  sein  konne.'J 


HISTORICAL  23 

tion,  but  others  have  placed  this  same  function  in  the  angular 
gyms,  to  which  it  will  be  remembered  Ferrier  assigned  such  im- 
portant visual  functions.  Optical  agnosia,  alexia  and  agraphia 
have  all  been  located  in  the  occipital  lobes,  but  usually  the  loca- 
tion has  been  so  indefinite  that  the  individual  localizations  can 
not  be  discussed  here.  It  may,  however,  be  said  that  the  more 
definite  localizations  are  localizations  in  areas  of  the  cortex  and 
of  the  underlying  white  matter  which  can  not  be  considered  part 
of  the  visuo-sensory  or  of  the  visuo-psychic  types  of  cortex.  An 
examination  of  the  diagrams  of  von  Monakow  and  of  Moutier  in 
comparison  with  the  cortical  differentiation  of  Brodmann,  of 
Campbell,  of  Bolton  and  of  Elliott  Smith  will  make  this  clear. 


EXPERIMENTAL. 

INTRODUCTION 

On  account  of  the  lack  of  information  in  regard  to  the  func- 
tions of  the  areas  (visuo-psychic)  believed  by  histologists  to  be 
closely  connected  with  the  visual  center  (calcarine  area),  it  ap- 
peared advisable  to  attempt  to  determine  the  functions  of  this 
so-called  psychic  area,  and  it  was  this  problem  which  originated 
the  present  work.  Subsequent  developments  directed  the  inquiry 
into  other  channels,  and  eventually  it  became  imperative  to  rein- 
vestigate  the  whole  occipital  lobe.  Only  part  of  the  work  has 
been  finished  but  sufficient  has  been  accomplished  to  indicate  that 
the  histological  differentiation  has  not  the  physiological  import 
which  the  histologists  impute  to  it.  The  present  work  deals  main- 
ly with  the  relations  of  the  lateral  aspect  of  the  occipital  lobes  in 
the  monkey  to  certain  sensory  and  perceptual  states. 

In  this  work  eight  monkeys  were  used,  each  of  which  was 
trained  in  visual  discrimination  previous  to  the  extirpation  or 
the  destruction  of  parts  of  the  occipital  cortex.  These  animals 
were  purchased  from  a  New  York  dealer,  and,  as  far  as  could  be 
ascertained,  had  not  been  used  for  experimental  purposes  or  for 
pets  before  the  time  of  purchase.  All  the  animals  were  reported 
to  be  about  six  to  nine  months  old  at  the  time  they  were  receiv  rl, 
although  in  size  there  was  a  considerable  variation.  During  the 
nine  months  following  their  purchase  they  were  utilized  by  Dr. 
W.  T.  Shepherd  in  psychological  investigation,  and  after  that 
period  they  were  entirely  in  my  charge.  During  the  time  they 
were  under  my  observation  they  were  fed  mainly  by  me,  but  at 
other  times  by  three  other  people.  The  animals  were,  therefore, 
well  acquainted  with  the  experimenter  and  they  acted  in  as  normal 
a  manner  as  could  be  expected  from  animals  kept  in  captivity. 
The  observations  of  the  animals  continued  for  about  fifteen 
months,  at  the  end  of  which  time  all  had  been  operated  upon  and 
killed.  The  animals  lived,  therefore,  approximately  two  years, 
during  which  time  they  were  under  almost  constant  observation, 


MONKEYS  25 

although  the  experiments  to  be  reported  in  the  present  paper  were 
not  being  conducted  throughout  all  this  period. 

Two  of  the  animals  upon  which  operations  were  performed 
were  shown  at  meetings  of  scientific  associations,  monkey  7  at 
the  meeting  of  experimental  psychologists  in  April,  1910,  and 
monkey  i  at  a  meeting  of  the  Georgetown  University  Clinical 
Society  in  February,  1910. 

During  the  time  the  animals  were  under  my  observation  they 
were  kept  in  pairs  or  by  threes  in  cages,  114  cm.  high,  90  cm. 
wide,  and  58  cm.  deep.  The  front  and  right  hand  ends  of  the 
cages  were  covered  with  chicken  wire,  of  one  and  one-half  inch 
mesh.  The  top,  the  bottom,  the  back  and  the  left  side  were 
boarded.  Within  the  cage  there  was  a  shelf  30  cm.  wide  jutting 
from  the  back  of  the  cage  at  a  height  of  about  45  cm.  This  shelf 
extended  the  width  of  the  cage.  From  the  front  of  this  shelf  to 
the  floor  of  the  cage  was  a  sliding  door.  When  an  experiment 
was  to  be  conducted  one  of  the  animals  (the  one  not  working) 
was  induced  to  get  below  the  shelf,  the  sliding  door  was  closed 
behind  it  and  the  monkey  confined  beneath,  leaving  the  second 
animal  free  so  that  the  experiments  might  be  conducted  without 
interruption  and  without  disturbances. 

The  sliding  door  was  kept  open  except  at  the  time  of  the  ex- 
periments, and  the  animals,  which  lived  in  these  cages  during 
the  progress  of  the  experiments,  ran  in  and  out  of  this  space 
as  they  wished.  There  was,  therefore,  no  cause  for  alarm 
on  the  part  of  the  animal  which  was  confined.  The  animals 
were  not  handled  and  the  environment,  except  for  the  presence 
of  the  experimenter,  was  kept  fairly  constant  throughout  the 
day.  Food  and  water,  other  than  that  used  in  the  experiments, 
were  pushed  through  or  under  the  wire  front  of  the  cage  and 
the  animals  took  as  much  food  as  they  wished. 

Notwithstanding  the  animals  were  not  handled,  all  became  fair- 
ly tame,  they  would  hang  upon  the  wire  netting  of  the  cage  and 
take  fruit,  nuts,  bread,  etc.,  directly  into  the  mouth,  and  at  no 
time  did  they  appear  to  be  disturbed  by  the  presence  of  the  ex- 
perimenter. 

In  the  accounts  of  the  work  which  will  be  found  in  the  section 
dealing  with  the  observations  of  the  animals  before  and  after  the 


26  SHEPHERD   IVORY   FRANZ 

operations,  it  will  be  found  that  there  are  many  expressions  simi- 
lar to  those  used  in  describing  the  actions  of  man.  It  must  not 
be  understood,  however,  that  these  expressions  are  used  in  the 
same  way  they  are  used  for  man,  but  solely  for  convenience  and 
for  brevity.  It  would,  perhaps,  have  been  advisable  to  describe 
the  actions  of  the  animals,  but  such  descriptions  to  be  intelligible 
must  be  accompanied  by  equally  minute  descriptions  of  the  situa- 
tions, and  from  the  visual  side  can  best  or  accurately  be  shown 
only  by  means  of  motion  pictures.  It  must  be  understood,  how- 
ever, that  the  anthropomorphic  method  of  describing  animal 
activity  is  not  to  be  taken  as  an  indication  that  the  animal  had  the 
same  sort  of  mental  process  which  a  man  would  have  under  simi- 
lar circumstances,  but  even  the  most  careful  of  the  animal  psy- 
chologists have  found  it  impossible  to  dispense  with  terms  des- 
criptive or  indicative  of  mental  processes  in  man.  It  would,  for 
example,  have  been  better  to  say  "the  animal  turned  its  head  and 
its  eyes  in  different  directions"  rather  than  "the  animal  peered 
around  the  cage"  but,  on  the  other  hand,  with  the  warning  that 
has  been  given,  no  one  should  interpret  the  animal  activity  in  a 
way  other  than  in  terms  of  movement. 

METHODS 

Training.  To  one  who  is  familiar  with  the  studies  on  the 
functions  of  the  cerebrum,  it  is  evident  that  many  of  the  differ- 
ences in  opinions  and  in  conclusions  have  been  due  to  the  fact 
that  the  tests  of  animals  upon  which  experiments  have  been  made 
have  been  of  such  a  character  that  they  permit  of  more  than  one 
interpretation.  It  is  certain  that  simple  observation  of  animals 
following  extirpation  of  parts  of  the  cortex  or  following  the 
injury  to  other  parts  of  the  nervous  system  is  an  inadequate 
method.  For  the  reason  that  both  the  description  of  results  of 
previous  physiological  work  on  the  association  areas  were  lacking 
in  exactness  and  defmiteness,  about  ten  years  ago,  the  writer 
(16-20)  devised  a  method  to  determine  more  accurately  the  sen- 
sory and  associative  functions  of  parts  of  the  nervous  system, 
especially  of  the  cerebrum.  The  first  investigation  to  be  per- 
formed by  this  method  was  one  on  the  association  functions  of 
the  frontal  lobes  (16,  17),  but  the  method  has  been  applied  to 


TRAINING  METHODS  27 

sensory  functions  both  in  the  present  work  and  in  work  published 
by  others.  This  method  has  previously  been  described  in  various 
places  and  at  present  it  may  be  said  that  it  depends  upon  the 
formation  of  definite  associations  in  an  animal  and  the  determin- 
ation of  the  presence  or  absence  of  the  associations  after  lesions 
of  the  nervous  system.  It  will  be  readily  appreciated  that  by  this  J 
method  there  is  an  approach  to  the  method  the  clinicians  use  in 
the  examination  of  their  human  cases,  and  there  is  afforded  the 
possibility  of  obtaining  very  exact  information  regarding  the 
sensory  or  associative  processes  of  animals  even  though  in  animal 
experimentation  we  are  hampered,  as  compared  with  the  investi- 
gations on  man,  by  the  lack  of  the  definite  means  of  communica- 
tion by  speech.9 

Before  an  animal  is  operated  upon  we  must  become  acquainted 
with  its  mental  character,  we  must  know  the  animal  well  before 
we  operate  so  that  we  shall  be  better  able  to  notice  deviations 
from  its  normal  mental  character,  following,  let  us  say,  the  loss 
or  the  destruction  of  a  certain  amount  of  a  certain  part  of  the 
brain  or  the  spinal  cord.  Usually  it  is  not  possible  to  keep  a 
laboratory  animal  for  a  period  of  months  or  years  in  order  to 

'  This  method  was  used  to  a  limited  extent  by  a  number  of  investigators 
before  it  was  applied  by  me  to  the  investigation  of  the  frontal  lobes,  but  all 
who  had  previously  used  it  had  employed  it  in  much  the  same  way  as  they 
made  their  regular  observations.  From  the  account  given  by  Kalischer  (36) 
of  an  investigation  of  the  functions  of  the  temporal  lobes  by  this  method, 
it  might  appear  to  one  unacquainted  with  the  situation  that  he  were  the 
originator  of  it.  He  calls  it  "meine  Dressurmethode."  To  an  impartial 
observer  it  appears  a  mere  hair  splitting  matter  to  differentiate  Kalischer's 
method  of  testing  hearing  in  dogs  from  that  of  Thorndike  (71),  but  through- 
out all  of  Kalischer's  work  there  is  evidence  of  total  ignorance  of  the  work 
which  has  been  performed  in  America  on  animal  psychology.  It  is  of  interest 
to  note  that  following  a  critical  note  by  me  (20)  Kalischer  (37)  relinquishes 
claim  to  the  method  as  a  whole,  but  makes  a  claim  that  he  has  used  the  most 
simple  movement  as  an  indication  of  the  presence  of  sensation  in  the  animal. 
This  claim,  in  the  way  it  is  made,  I  am  sure  no  comparative  psychologist  will 
admit,  for  the  movement  of  the  paw,  or  the  movement  of  walking,  is  just 
as  simple  physiologically  as  the  movement  which  Kalischer  has  used,  viz., 
that  of  the  snapping  up  of  food,  which  must  have  associated  with  it  other 
movements  of  the  head.  It  is  also  of  interest  to  note  that  Kalischer  admits 
in  his  second  article  (37)  some  acquaintance  with  the  training  method  that 
had  been  used  by  others  (e.  g.,  Gaule,  21),  although  no  mention  is  made  of 
this  in  his  first  article. 


28  SHEPHERD   IVORY  FRANZ 

get  acquainted  with  its  mental  make-up,  and  to  facilitate  matters 
we  have  at  our  command  the  training  method  devised  by  Lloyd 
Morgan  and  so  ably  followed  out  by  Thorndike  (71)  and  many 
others.  By  the  use  of  this  method  we  may  have  animals,  which 
are  to  be  operated  upon,  form  certain  associations,  the  presence 
or  absence  of  which  can  be  later  determined  by  the  experimenter 
in  a  few  minutes.  The  associations  always  involve  two  elements, 
the  sensory  or  afferent,  and  the  motor  or  efferent.  It  is  believed 
that  in  most,  if  not  all,  cases  a  third  element  is  present,  viz.,  the 
associational.  By  proper  combinations  and  by  the  formation  of 
more  than  one  habit  at  a  time  it  is  possible  to  differentiate  these 
three  elements,  and  to  infer  without  question  which  of  the  ele- 
ments is  lacking  and  which  has  been  interfered  with. 

Comparative  psychologists  have  investigated  the  visual  dis- 
crimination ability  of  monkeys,  but  some  have  not  been  satisfied 
from  the  results  and  the  methods  of  the  experiments  that  mon- 
keys discriminate  colors  as  such.  The  methods  of  other  investi- 
gators and  the  results  obtained  by  them  indicate  that  monkeys 
have  good  visual  discrimination,  although  a  few  are  unwilling  to 
admit  the  conclusiveness  of  the  experiments  on  color.  It  seemed 
advisable  to  have  the  animals  acquire  a  habit  indicative  of  color 
discrimination  but  none  of  the  methods  previously  employed  ap- 
peared to  be  sufficiently  well  accepted  and  none  appeared  to  place 
the  animal  in  a  position  similar  to  that  it  might  normally  be  in. 
In  the  present  work  an  attempt  was  made  to  have  the  animal  test- 
ed in  as  normal  a  way  as  possible,  and  to  form  the  habit  or  to 
produce  the  discrimination  quickly  as  well  as  naturally. 

In  the  present  work  it  was  necessary  to  have  the  animals  form 
habits  of  a  definite  visuo-motor  character.  For  this  reason  the 
sensory  part  was  made  as  simple  as  possible,  viz.,  foods  of  dif- 
ferent colors,  which  had  to  be  discriminated.  In  a  series  of 
experiments  on  the  color  discrimination  of  monkeys,  conducted 
by  Dr.  W.  T.  Shepherd  (68),  under  my  direction  it  was  found 
that  the  animal  rapidly  learned  to  discriminate  colored  objects 
if  the  stimuli  were  of  a  character  to  attract  and  to  hold  the  atten- 
tion. In  most  animal  experimentation  it  has  been  found  difficult 
to  get  stimuli  which  will  attract  the  attention  of  the  animal, 
stimuli  which  are  appreciated  by  the  animal  and  which  will  lead 


TRAINING  METHODS  29 

to  definite  reactions.  In  color  experiments  it  has  been  customary 
to  use  the  box  method  of  feeding,  the  box  being  covered  with 
colored  paper  or  lights  being  exposed  near  the  box.  The  employ- 
ment of  this  method  has  certain  advantages  and  certain  disadvan- 
tages that  are  apparent  to  all  who  have  used  it.  On  the  one  hand 
the  colors  may  be  changed  to  a  considerable  degree  both  in  inten- 
sity and  in  hue,  but  on  the  other  hand  the  use  of  papers,  filters, 
or  other  similar  means  of  giving  stimuli  introduces  an  element 
foreign  to  the  animal  mind  and  must  have  less  effect  than  the 
exhibition  of  colors  in  direct  connection  with  the  object  to  be 
obtained.  Moreover,  in  order  to  determine  discrimination  ability 
many  investigators  have  found  it  necessary  to  punish  the  animal 
for  a  wrong  selection  and  to  reward  it  by  means  of  food  for  a 
correct  selection.  In  most  of  the  work  which  has  been  reported 
the  punishment  has  also  been  something  foreign  to  the  animal 
mind,  and  the  use  of  electric  shocks  and  other  similar  methods 
to  inhibit  the  activities  of  an  animal  have  led  at  times  to  disturb- 
ances in  activity  which  are  not  conducive  to  proper  experimenta- 
tion. 

Because  of  the  difficulties  and  disadvantages  of  the  methods 
which  have  been  previously  employed,  colored  food  was  used  in 
the  experiments  of  Dr.  Shepherd,  and  in  these  experiments  it 
could  not  be  doubted  that  the  attention  of  the  animal  was  directed 
toward  the  stimuli.  In  the  early  work  bread  or  rice  was  mixed 
with  appropriate  colors,  two  or  more  differently  colored  pieces 
of  food  were  simultaneously  displayed  before  the  animal  and  the 
animal  learned  to  select  one  or  more  of  the  colored  pieces.  The 
artificial  method  of  punishment  was  discarded  in  these  experi- 
ments and  a  more  natural  method  was  employed.  In  the  method 
the  punishment  and  the  cause  of  the  inhibition  of  the  wrong  re- 
actions were  contained  in  the  stimuli  and  were  not  extraneous. 
Certain  of  the  colored  foods  were  soaked  with  a  solution  of  qui- 
nine and  others  had  added  to  them  a  certain  amount  of  saccharine. 
On  the  assumption  that  the  monkey  likes  sweet  and  dislikes  bitter 
tasting  foods,  we  should  find  that  the  animal  would  learn  to  de- 
cline the  bitter  food  and  to  take  only  those  which  were  sweet  or 
at  least  not  bitter.  As  a  matter  of  fact,  this  assumption  wa^ 
found  to  hold  in  almost  all  the  animals  tested.  With  only  one 


SHEPHERD   IVORY  FRANZ 


monkey  was  there  any  difficulty  in  the  establishment  of  the  habit 
to  take  the  properly  colored  and  sweetened  food  and  to  leave  the 
food  which  had  been  made  bitter.  This  animal  seemed  to  have 
little  objection  to  the  bitter  taste  and  for  a  relatively  long  time 
ate  both  the  sweet  and  the  bitter  foods.  This  animal  died  before 
the  effects  of  the  operation  were  determined  and  the  records  are 
not  included  in  the  accounts  of  the  experimental  work.  Eight 
other  monkeys,  however,  had  a  decided  dislike  for  bitter  food,  or 
to  express  this  in  terms  of  reaction,  these  animals  soon  learned  to 
permit  the  bitter  foods  to  remain  on  the  plate,  and  although  hun- 
gry, did  not  touch  them.  In  the  formation  of  the  habit  and  in 
the  subsequent  tests  following  the  operation  the  monkeys  were 
not  kept  in  a  state  of  absolute  hunger,  for  it  was  found  by  pre- 
vious work  that  this  factor  would  interfere  with  the  normal  work- 
ing of  a  monkey. 

In  performing  the  experiments  to  be  described  here  the  animal 
was  in  its  usual  cage.  The  cage  has  already  been  described.  The 
animal  sat  upon  the  shelf,  sometimes  near  the  wire  netting  on  the 
right  hand  side  and  sometimes  farthest  away  from  the  netting. 
A  glass  plate,  12.5  by  18  cm.,  was  arranged  on  a  platform  with 
cup  hooks  to  catch  the  wire  of  the  cage  so  that  it  could  be  at- 


9 


FIG.  9.    Glass  plate  and  holder  for  the  presentation  of  food  to  the  monkeys, 
A,  glass  plate;  B-B,  cup  hooks  to  catch  upon  the  wire  netting  of  the  cage. 


TRAINING  METHODS  31 

tached  to  any  part  of  the  front  or  side  of  the  cage.  The  arrange- 
ment was  such  that  the  glass  plate  was  kept  horizontal.  Fig.  9 
illustrates  the  glass  plate  and  the  holder.  All  this  part  of  the 
apparatus  was  colored  black.  The  food  was  placed  upon  the 
glass  plate,  the  holder  was  arranged  on  the  cage  and  the  experi- 
menter moved  away  from  the  cage  about  a  meter's  distance.  The 
animal,  which  usually  sat  at  the  farthest  end  of  the  platform, 
moved  forwards  and  took  the  food  which  was  presented  to  it  on 
the  plate.  In  performing  the  experiment  in  this  manner  the 
greatest  possible  freedom  was  accorded  the  animal,  and  the  move- 
ment to  be  performed  was  as  simple  as  possible  and  one  which 
would  give  the  right  to  conclude  that  discrimination  did  or  did  not 
take  place,  i.  e.,  the  taking  or  leaving  of  the  food.  The  arrange- 
ments at  a  later  date  were  made  more  simple,  as  far  as  the  ad- 
justments are  concerned,  in  that  the  glass. plate  holder  was  at- 
tached to  the  cage  at  the  beginning  of  the  series  of  tests  and  kept 
there  throughout  the  series  on  that  day.  When  this  was  done  the 
food  was  placed  upon  the  plate  in  the  same  manner  as  has  been 
described.  In  all  the  series  of  tests  the  arrangements  of  the  breads 
were  constantly  changed,  the  bitter  being  at  times  on  the  right,  at 
times  on  the  left,  and  if  three  or  four  pieces  were  simultaneously 
displayed  the  bitter  pieces  were  between  the  sweet,  or  at  both 
f.nds.  In  most  of  the  experiments,  all  of  those  in  which  the 
animal  was  being  trained,  the  two  or  more  pieces  of  food  were 
placed  upon  the  plate  at  approximately  the  same  distance  from 
the  cage  netting.  In  later  tests  at  times  the  foods  were  arranged 
indiscriminately  on  the  plate,  the  sweet  being  farther  from  or 
nearer  the  cage,  etc.  Most  of  the  animals  were  trained  on  the 
discrimination  of  colored  foods,  and  one  on  the  discrimination  of 
foods  of  different  sizes. 

The  colored  food.  After  a  number  of  tests  it  was  found 
that  white  bread  was  most  suitable  both  for  coloring  and  for 
food.  The  bread  was  usually  24  to  48  hours  old  at  the  time 
it  was  received.  The  crust  was  removed  and  the  bread  was  cut 
into  thin  slices  about  5  mm.  thick,  then  into  strips  of  about  the 
same  width,  and  finally  into  shorter  lengths  making  hexahedrons, 
approximately  cubes,  5  mm.  on  each  edge.  A  large  number  of 
these  were  cut  at  one  time  and  from  30  to  100,  depending  upon 


32  SHEPHERD   IVORY  FRANZ 

the  number  of  animals  under  the  test,  were  colored ;  the  remain- 
der were  used  on  succeeding  days.  If  kept  uncovered  the  small 
cubes  dried,  but  it  was  found  that  the  immersion  into  the  solu- 
tions brought  them  back  to  their  original  size.  The  cubes  were 
dipped  into  watery  solutions  of  different  colors,  and  thoroughly 
saturated.  The  resultant  colors  were  fairly  homonymous,  but 
did  not  have  the  smoothness  of  colored  papers  or  of  other  similar 
material  on  account  of  the  small  bubble  holes  in  the  bread.  The 
colored  moist  breads  were  placed  in  small  crystallizing  dishes  and 
covered  with  watch  glasses  to  prevent  the  entrance  of  dust  and 
to  limit  evaporation.  In  this  way  it  was  found  possible  to  make 
up  fairly  large  quantities  of  the  different  colors  and  to  keep  them 
fresh  and  moist  for  several  days. 

In  the  general  experiments  on  color  four  differently  colored 
breads  were  prepared :  red,  blue,  green,  and  yellow.  The  color 
solutions,  formulae  for  which  follow,  were  made  up  in  large 
quantities,  and  to  each  solution  a  proportionate  quantity  of  alco- 
holic solution  (5%)  of  thymol  was  added.  The  thymol  was 
added  for  two  reasons ;  first  to  prevent  the  formation  of  mold  in 
the  solution  and,  secondly,  to  overcome  any  special  odor  of  the 
solution  and  to  substitute  for  the  special  odor  that  of  thymol.  In 
this  way  an  attempt  was  made  to  equalize  the  odors  of  all  the 
stimuli,  in  order  that  the  discrimination  might  not  take  place  be- 
cause of  the  differences  in  odor.  Particular  attention  is  cal:ed 
to  this  factor,  for  although  we  have  no  right  to  say  that  by  this 
introduction  of  a  foreign  odor  (distinctly  perceptible  to  man) 
the  odors  of  all  the  pieces  of  bread  were  the  same,  I  believe  the 
strength  of  the  solution  was  sufficient  to  overcome  any  odor  of 
the  individual  solutions.  None  of  the  individuals  (men)  who 
were  tested  could  detect  the  least  difference  in  the  odors  of  the 
solutions,  and  the  tentative  conclusion  was  drawn  that  the  indi- 
vidual odors  of  the  solutions  were  overcome,  and  that  all  the 
breads  smelled  alike. 

The  formulae  used  in  making  the  solutions  were  as  follows : 

Red :  Congo    red i.o  gram. 

Water    300.0  cc. 

Saccharine 3-O  grams. 


33 

Blue :  Toluidin    blue     0.5  gram. 

Water     400.0  cc. 

Saccharine     4.0  grams. 

Yellow :  Methyl    orange    0.5  gram. 

Water    250.0  cc. 

Quinine  bisulphate    (0.5%  solution) 25.0  cc. 

Green :  Methyl    orange    0.2  gram. 

Smaragd  grim  o.i  gram. 

Water     250.0  cc. 

Quinine  bisulphate    (0.5%  solution) 25.0  cc. 

When  they  were  intended  for  use,  i.  e.,  for  the  dipping  of  the 
bread,  the  solutions  were  diluted  to  one-half  strength  by  the 
addition  of  water. 

Immediately  after  dipping  the  breads  the  colors  of  the  breads 
were  compared  with  the  colored  papers  in  the  Milton-Bradley 
series.  On  this  comparison  it  was  found  that  the  yellow  bread 
was  approximately  half-way  between  the  yellow  orange  and  the 
orange  yellow  of  that  scale,  but  after  slightly  drying  the  color 
was  more  nearly  like  the  latter.10  The  red  bread  was  approximate- 
ly like  the  red  of  the  scale,  although  on  account  of  the  chemical 
properties  of  the  Congo  red  this  color  varied  to  a  greater  extent 
than  did  any  of  the  others.  When  the  bread  was  dipped  into  the 
blue  solution  it  took  a  color  most  like  that  of  the  Engine  colored 
paper  5b  of  the  scale,  being  close  to  the  regular  blue  shades  nos. 

1  and  2.     When  the  solution  was  diluted  to  half  strength,  as 
usual,  the  bread  became  nearly  like  Engine  colored  paper  5,  or 
like  the  blue  of  the  regular  scale,  although  the  latter  was  a  trifle 
darker.    The  bread,  after  having  been  dipped  into  the  green  solu- 
tion almost  exactly  matched  green  yellow  shade  i,  but  on  stand- 
ing this  color  changed  to  yellow  green  shade  2,  and  eventually 
became  almost  like  yellow  green.     The  change  in  this  case  was 
probably  due  to  some  combination  with  the  air,  probably  oxida- 
tion. 

No  special  examination  of  the  colored  solutions  by  means  of 

10  The  colors  of  the  breads  are  given  in  terms  of  the  nearest  color  in  the 
Milton-Bradley  scale,  but  the  comparison  is  rough,  and  in  the  case  of  green 
2,  the  color  scale  showed  nothing  to  correspond  closely.  The  color  of  green 

2  was  much  darker  than  the  M-B  green  shade  no.  2,  but  there  is  nothing  irr 
that  scale  to  give  a  better  idea  of  the  color  and  shade.     The  difference  in 
the  colors,  is,  however,  the  main  fact  to  be  remembered. 


34  SHEPHERD   IVORY  FRANZ 

the  spectroscope  or  by  the  photometer  was  made,  because  all  the 
colors  are  standard  colors,  and  can  readily  be  made  by  anyone, 
and  because  this  examination  was  not  deemed  of  importance  in 
the  present  work. 

Color  Vision  of  the  Monkey.  It  has  been  said  above  that  the 
animals  soon  learned  to  discriminate  the  colored  breads,  leaving 
the  bitter  ones  and  taking  the  sweet.  At  first  this  may  be  taken 
as  sufficient  evidence  that  the  discrimination  was  made  on  the 
basis  of  the  color  quality,  but  to  this  conclusion  many  animal 
psychologists  will  take  exception.  On  account  of  the  doubt  on 
this  point  a  supplementary  series  of  tests  were  made  with  several 
monkeys  to  determine  whether  the  hue  or  the  difference  in  inten- 
sity (or  brightness)  was  the  factor  which  was  discriminated.  The 
tests  of  one  animal  will  suffice  to  make  this  matter  clear. 

With  this  animal  breads  colored  red  and  green  were  employed. 
After  the  animal  had  learned  to  discriminate  the  two  kinds  of 
bread,  the  colors  were  changed  in  intensity  or  in  saturation  and 
additional  tests  were  then  made.  In  the  original  tests  (before 
the  changes  in  the  intensity,  etc.,  of  the  colors)  in  making  up 
different  lots  of  colored,  breads  the  pieces  showed  slight  differ- 
ences in  intensity  and  in  saturation,  and  to  a  greater  extent  in 
moisture.  These  variations  were  not  of  sufficient  amount  to  be 
particularly  noticeable  by  me  or  by  others,  and  were  determined 
only  when  the  breads  colored  at  different  times  were  placed  side 
by  side  and  examined  in  very  bright  light.  There  was  also  a 
very  slight  difference  in  the  colors  of  the  individual  pieces  of 
bread,  but  under  the  most  favorable  conditions  these  differences 
-could  not  be  detected  at  a  distance  of  about  a  meter.  In  per- 
forming the  experiments  the  colors  were  placed  on  the  plate  sim- 
ultaneously but  in  an  irregular  position ;  half  of  the  time  the  reel 
was  to  the  right  of  the  animal  and  half  to  the  left.  Sometimes  the 
red  and  sometimes  the  green  was  nearer  the  animal.  In  this  way 
no  association  could  be  formed  between  positions  and  the  tastes. 

Experiments  in  color  (beyond  these  performed  by  Dr.  Shep- 
herd, to  whose  work  reference  has  been  made)  began  with  mon- 
key 6  on  November  30.  On  that  day  in  the  first  test  the  animal 
took  both  pieces  of  bread,  red  and  green,  and  immediately  placed 
them  in  her  mouth  and  ate  them.  She  did  not  appear  to  enjoy  the 


COLOR  VISION  OF  THE  MONKEY  35 

taste  of  one  of  the  pieces  and  became  more  cautious  after  two 
trials,  and  on  the  third  trial  she  partly  rejected  the  green  (bitter). 
On  seven  other  trials  on  this  day  the  animal  took  only  the  .red 
bread  (sweet).  On  the  following  day  she  took  only  the  red. 
Three  days  later  she  took  both  the  red  and  the  green  in  the  first 
seven  trials,  and  only  the  red  the  other  three  trials.  A  rest  of 
two  days  was  given,  and,  following  this,  on  twelve  successive 
days,  ten  trials  each  day,  there  were  only  three  mistakes.  At  the 
end  of  this  time  it  was  concluded  the  habit  was  firmly  established. 
The  animal  would  not  take  the  green  bread,  no  matter  what  posi- 
tion it  occupied  on  the  plate.  At  times  the  red  bread  was  placed 
as  far  away  as  possible,  and  at  other  times  to  the  extreme  right  or 
to  the  extreme  left  while  the  green  was  in  the  most  prominent 
place,  viz.,  the  center  of  the  glass. 

On  the  following  day  the  conditions  of  the  experiment  were 
altered.  Instead  of  presenting  to  the  animal  only  the  definite  col- 
ors with  which  it  had  become  familiar  and  to  which  it  had  learned 
to  react  in  a  definite  way,  marked  variations  of  these  colors  were 
presented.  Each  of  the  stock  solutions  for  this  experiment  was 
mixed  with  different  quantities  of  water,  and  in  this  way  there 
was  obtained  solutions  giving  (to  man)  four  distinct  shades  of 
red  and  four  of  green.  The  mixtures  which  gave  the  different 
colors  and  the  color  results  on  the  bread  (according  to  the  Milton- 
Bradley  scale)  of  saturating  the  bread  with  these  mixtures  are 
as  follows : 

Red  I — (red,  shade  no.  2)   16  cc.  standard  red  solution,  40  cc.  water,  and 

a  piece  of  sodium  carbonate  the  size  of  the  head  of  a  pin.11 
Red  2 — (red)     16    cc.    standard    red    solution,    40    cc.    water,    and    sodium 

carbonate  until  the  solution  began  to  clear. 
Red  3 — (orange    red)     16    cc.    standard    red    solution,    40    cc.    water,    and 

sodium  carbonate  until  the  solution  became  clear. 
Red  4 — (red,  tint  no.  2)    10  cc.  standard  red  solution,  50  cc.  water,  and 

sodium  carbonate  until  the  solution  became  clear. 
Green  i — (yellow  green,  shade  no.  2)   20  cc.  standard  green  solution  and 

50  cc.  water. 

11  The  Congo  red  is  an  indicator  for  acids  and  alkalies,  and  the  color  ot 
the  solution  depends  upon  the  relative  amounts  of  these  opposing  conditions. 
The  color  of  the  solution  was  readily  altered  by  the  addition  of  small  quanti- 
ties of  sodium  carbonate  and  the  greater  or  less  quantity  of  this  alkali  gave 
the  various  shades  and  tints  of  the  red. 


36  SHEPHERD   IVORY  FRANZ 

Green  2 — (green,  shade  no.  2)   35  cc.  standard  green  solution,  and  20  cc. 

water. 
Green  3 — (green,  tint  no.  i)  15  cc.  standard  green  solution,  and  25  cc. 

water. 
Green  4 — (yellow  green,  tint  no.  i)  10  cc.  standard  green  solution  and 

50  cc.  water. 

Two  of  these  colored  pieces  of  bread  were  presented  to  the 
monkey  in  the  same  manner  as  the  breads  to  which  it  had  learned 
to  react.  The  breads  were  selected  and  arranged  in  an  irregular 
order ;  red  i  and  green  i ;  red  i  and  green  2 ;  red  2  and  green  i ; 
red  3  and  green  3,  etc.  With  these  combinations  twenty  tests 
were  made  and  in  every  test  the  animal  took  the  red  bread  and 
disregarded  the  green.  Twenty  tests  on  each  of  two  succeeding 
days  gave  the  same  result;  green  of  any  shade  or  tint  was  not 
taken,  the  red  bread  of  any  shade  or  tint  was  taken.  Three  days 
later  twenty-two  tests  with  two  of  the  colors  gave  almost  the 
same  result,  and  two  tests  in  which  two  pieces  of  green  and  two 
pieces  of  red  were  presented  simultaneously  showed  that  the  ani- 
mal would  take  the  red  and  disregard  the  green  even  when  the 
conditions  of  the  test  were  changed  in  this  particular.  Follow- 
ing is  a  record  for  this  day : 

December  23,  1909.  Monkey  6,  reactions  to  shades  and  tints  of  red  and 
green.  Ri,  R2,  R3,  R4,  Gi,  G2,  G3,  G4,  are  the  different  shades  and  tints 
used.  The  color  noted  first  in  each  test  was  placed  at  the  left  of  the  plate. 

1.  Ri,  Gi.  9.  G4,  Ri.  17.  G3,  R3. 

2.  R2,  G2.  10.  G4,  R2.  18.  R4,  63. 

3.  R3,  G3.  ii.  G2,  Ri.  19.  G4,  Ri. 

4.  R4,  G4.  12.  G2,  R2.  20.  R2,  G4. 

5.  Ri,  G4.  13.  R3,  G2.  21.  R3,  G4. 

6.  G4,  R4.  14.  R4,  G2.  22.  R4,  64. 

7.  R2,  G4.  15.  Ri,  G3.  23.  Ri,  Gi,  G4,  R4. 

8.  G4,  R3.  1 6.  G3,  R2.  24.  R2,  G2,  R3,  63. 

In  test  4  the  monkey  took  the  red  piece  first  and  after  it  the 
green ;  in  all  other  tests  only  red  was  taken.  Eighteen  days  later 
the  monkey  made  no  mistakes  in  13  trials  with  two  pieces  pre- 
sented simultaneously.  Following  is  the  order  of  the  tests : 

1.  Ri,  G2.  6.  G4,  R3.                      ii.  Gi,  K4- 

2.  G2,  R3.  7.  G4,  R2.                      12.  R2,  Gi. 

3.  G2,  R2.  8.  R4,  G4-                      13.  R4,  G3. 

4.  R4,  G2.  9.  Ri,  Gi. 

5.  Ri,  G4.  10.  Gi,  R3. 


COLOR  VISION  OF  THE  MONKEY  37 

Another  monkey  which  was  tested  picked  out  the  shades  and 
tints  of  red  when  the  number  presented  simultaneously  was  more 
than  four,  and  two  other  animals  made  no  mistakes  on  the  differ- 
ent shades  at  a  later  date  although  the  colors  were  not  so  defined 
as  they  were  in  these  experiments.  Even  when  other  colored  so- 
lutions were  used  for  the  dipping  of  the  bread  the  animal  always 
selected  the  red  in  preference  to  the  green.  In  some  of  the  later 
tests  the  red  bread  was  made  by  dipping  the  pieces  into  Carter's 
crimson  ink,  and  the  green  by  dipping  pieces  into  a  mixture  of 
blue  and  yellow  drawing  inks  (Columbia  brand).  These  later 
tests  were  made  also  without  having  the  solution  mixed  with 
thymol  solution,  and  without  the  addition  of  saccharine  and  qui- 
nine. It  appears  from  these  tests,  therefore,  that  neither  the 
smell  of  the  thymol  nor  the  presence  of  the  saccharine  affected 
the  reaction  after  the  habit  was  established  and  that  the  reaction 
Avas  one  due  to  the  color  of  the  breads. 

In  further  tests  with  monkey  6  in  which  some  of  the  colored 
pieces  of  bread  were  of  a  larger  size,  10  to  12  mm.  on  each  edge, 
and  some  were  of  the  smaller  usual  size,  the  combinations  of  the 
small  with  the  large  did  not  affect  the  reaction  to  the  color.  The 
following  combinations  were  made:  A,  small  red  with  a  large 
green ;  B,  small  red  with  small  green ;  C,  large  red  with  large 
green ;  D,  large  red  with  small  green ;  tints  and  shades  varying 
as  has  been  described.  In  these  tests  the  red  was  selected  re- 
gardless of  size,  tint  or  shade ;  the  green  was  always  disregarded. 

The  results  of  these  experiments  indicate  plainly  that  the  mon- 
key  which  has  been  taught  to  react  to  a  particular  situation  is 
able  in  some  way  to  transfer  this  practice  to  a  situation,  which 
has  certain  elements  of  similarity,  or,  to  put  the  matter  in  more 
definite  terms,  the  monkey  which  has  learned  to  react  to  definite 
colored  objects  in  some  manner  extends  this  mode  of  reaction 
to  shades  and  tints  of  the  same  hues.  Two  explanations  may  be 
offered  for  this  result;  that  the  animal  has  in  each  case  reacted 
to  the  hue  of  the  object  or  that  it  has  reacted  to  some  other  factor. 
The  experiments  with  the  different  sizes  shows  that  the  reaction 
was  not  to  size.  The  fact  that  the  colored  breads  were  placed  on 
the  plate  in  irregular  order  indicated  that  the  reaction  was  not 
due  to  the  position.  Because  the  animal  disregarded  the  differ- 

>  <   t  i  ; 
L  £  A  1 1  ,) 


38  SHEPHERD   IVORY  FRANZ 

ence  in  intensity  of  the  colors  and  continued  to  react  in  an  appro- 
priate manner  regardless  of  the  intensity  differences  is  an  indica- 
tion that  the  intensity  relations  of  the  breads  was  not  the  impor- 
tant factor,  and  because  other  reds  and  greens  (with  presumably 
different  absorption  spectra,  although  this  was  not  determined) 
were  selected  by  the  monkey  in  the  same  manner,  the  indication 
appears  plain  that  the  reaction  was  due  to  the  color  or  hue.  From 
the  tests,  especially  when  we  compare  them  with  other  tests  on 
animals  performed  by  others,  it  seems  justified  to  conclude  that 
monkeys  do  discriminate  colors,  and  that  in  the  present  work 
the  discrimination  was  one  of  color  and  not  of  other  elements  in 
the  stimuli. 

Operation.  Each  monkey  was  caught  in  a  bag  and  anesthetized 
in  it  before  being  prepared  for  the  operation.  This  was  found 
to  be  necessary  on  account  of  the  struggles  of  the  animal  from 
the  anesthetic  and  binding,  and  after  the  anesthetic  was  begun  it 
was  continued  throughout  the  time  the  operation  was  in  progress. 
As  an  anesthetic  I  used  the  A.  C.  E.  mixture.  This  I  found  was 
well  taken  by  the  animals,  it  decreased  the  time  of  excitement, 
and  was  much  safer  than  when  chloroform  alone  was  given.  The 
recovery  was  rapid  and  attended  by  no  adverse  conditions. 

After  having  been  anesthetized  the  animal  was  placed  upon  an 
operating  board,  and  tied  thereto.  The  hair  over  the  head  and 
over  the  back  of  the  neck  was  cut  closely,  and  over  the  part  where 
the  incision  was  to  be  made  a  depilatory  solution  or  paste  was 
applied.  This  was  found,  as  in  my  previous  work,  to  be  an  ex- 
cellent method  of  removing  the  hair,  and  was  much  easier  than 
the  method  of  shaving.  In  shaving  it  has  been  found  that  the 
skin  is  sometimes  broken  and  this  introduces  an  extra  wound 
which  must  be  attended  to  or  the  chance  of  infection  is  increased. 
Moreover  the  depilatory  produced  a  "close  shave"  removing  the 
fine  hairs  as  well  as  the  coarse  ones.  The  mixture  employed  by 
me  was  made  by  combining  equal  parts  of  precipitated  chalk  and 
barium  sulphide,  and  adding  sufficient  sterile  water  to  make  a 
paste.12  This  was  applied  to  the  head,  as  has  been  mentioned  and 

12 1  tried  upon  myself  various  mixtures,  but  found  the  most  satisfactory 
results  to  be  obtained  with  the  mixture  of  chalk  and  sodium  sulphide,  calcium 
sulphide,  and  barium  sulphide.  The  calcium  and  sodium  sulphides  did  not 
work  as  rapidly  as  the  barium,  and  were  apparently  more  irritating,  so  that 
in  all  the  experiments  with  the  monkeys  the  barium  sulphide  was  employed. 


OPERATIONS  39 

in  from  three  to  five  minutes  the  hair  was  removed  by  scraping 
away  the  paste.  The  head  was  then  washed  with  bichloride  solu- 
tion, i  :  looo,  and  a  gauze  sponge  soaked  in  the  solution  of  bi- 
chloride was  applied  to  the  head,  and  left  there  until  the  operation 
was  begun,  i.  e.,  about  3  to  5  minutes. 

The  i-nstruments  had  been  sterilized  by  boiling  in  a  solution  of 
sodium  carbonate,  and  the  dressings  had  been  sterilized  in  a 
pressure  steam  sterilizer.  After  having  carefully  attended  to  the 
matter  of  sterilization,  the  operation  was  begun.  The  apparently 
great  trouble  taken  for  the  production  of  asepsis  was  repaid  by 
the  results  of  the  operations,  in  only  one  of  which  were  signs  of 
infection  found,  and  this  case  was  readily  explained  and  will  be 
mentioned  below. 

A  median  incision  was  made  in  the  scalp  and  a  second  one  was 
made  at  right  angles  to  the  original  one,  about  at  the  place  the 
skull  openings  were  to  be  made.  The  skull  was  opened  by  the 
use  of  a  half-inch  trephine,  and  in  most  of  the  operations  this 
opening  was  enlarged  by  bone  forceps  to  three  or  four  times  the 
original  size.  In  some  of  the  operations  the  brain  was  incised 
with  a  fine  cataract  knife,  for  the  purpose  of  separating  the 
occipital  lobe  from  the  remainder  of  the  brain,  but  in  most  of  the 
operations  the  cortex  was  cauterized  by  means  of  a  galvano-cau- 
tery.  The  depth  of  the  burning  varied  in  each  case,  in  each  hemi- 
sphere and  even  in  different  parts  of  the  hemisphere,  but  these 
results  will  be  mentioned  in  the  appropriate  experimental  sections. 
The  trephine  buttons  were  seldom  inserted.  Bleeding  from  the 
cliploe  was  checked  by  the  application  of  bone  wax,  and  the  bleed- 
ing of  the  brain  was  usually  controlled  by  the  application  of  com- 
presses wet  with  normal  saline  solution.  At  times  it  was  neces- 
sary to  apply  a  small  quantity  of  Suprarenalin,  i  :  1000,  which 
effectively  checked  the  hemorrhage  when  it  was  used. 

After  the  operative  interference  with  the  brain  the  dura  was 
drawn  over  the  brain,  but  was  not  sutured.  The  scalp  wound  was 
closed,  and  over  the  site  of  the  scalp  wound  a  layer  of  gauze 
slightly  thicker  over  the  site  of  the  removal  of  the  bone,  was 
placed.  A  cotton  bandage  was  then  arranged  around  the  head, 
to  include  the  jaw,  but  leaving  out  the  ears.  After  sufficient  lay- 
ers of  this  had  been  applied  it  was  sewn  with  strong  thread  to 


40  SHEPHERD   IVORY  FRANZ 

prevent  its  removal  by  the  animal.  The  bandage  was  picked  at 
by  the  animal  but  in  no  case  in  which  the  sewing  was  thoroughly 
performed  did  the  monkey  cause  it  to  fall  off.  The  constant 
picking  frayed  the  edges  and  after  a  few  weeks  the  bandage  en- 
tirely disappeared  from  the  head,  and  was  found  encircling  the 
neck  like  a  ruching.  Long  before  this  time,  however,  the  wound 
had  healed  and  the  removal  of  the  bandage  did  not  affect  the 
wound.  After  the  bandage  was  removed  it  was  usually  found 
that  the  hair  had  begun  to  grow.  With  one  animal  the  bandage 
was  hurriedly  sewed,  on  account  of  the  rapid  recovery  from  the 
anesthetic,  and  the  whole  bandage  was  found  to  have  been  re- 
moved within  three  hours  after  the  operation.  Even  this  animal 
did  not  show  signs  of  infection  at  the  autopsy.  In  this  case  a 
new  bandage  was  applied  after  the  head  was  thoroughly  washed 
with  bichloride  solution. 

Post  Mortem  Examinations.  One  animal  was  killed  with  illu- 
minating gas,  and  the  others  were  given  overdoses  of  chloroform. 
In  most  cases  the  autopsy  was  performed  immediately  after 
death,  and  in  only  one  was  there  a  delay  of  as  much  as  two  hours. 
The  brains  were  weighed  as  a  whole,  and  no  effort  was  made  to 
separate  the  cerebrum  from  the  cerebellum  and  pons,  etc.,  nor  to 
get  the  separate  weights  of  the  hemispheres.  It  was  found  incon- 
venient at  times  to  get  the  brains  weighed  at  the  time  of  the  autop- 
sy, and  those  which  were  not  weighed  at  the  time  of  the  autopsy 
were  weighed  after  having  been  preserved  in  alcohol  (95%)  or 
in  formalin  (10%)  for  24  hours. 

Some  of  the  brains  were  photographed  immediately  after  the 
autopsy,  but  a  few  were  photographed  after  having  been  in  alco- 
hol or  in  formalin.  From  the  photographs  tracings  were  made, 
showing  all  the  principal  points,  fissures,  etc.,  and  the  illustra- 
tions accompanying  this  article  are  reproductions  of  these  trac- 
ings. Whenever  a  brain  was  photographed  it  was  placed  on  a 
scale  showing  centimeter  and  half  centimeter  divisions,  and  these 
divisions  are  marked  in  the  illustrations.  The  surface  diagrams 
are,  therefore,  approximately  accurate  representations,  and  on 
account  of  the  presence  of  the  scale  the  accurate  sizes  of  the 
brains  may  be  determined.  The  illustrations  are  reductions  from 
the  tracings,  in  some  cases  to  one-half  size,  in  others  to  two-thirds. 


POST  MORTEM  EXAMINATIONS  41 

size  of  the  originals.  When  the  hemispheres  were  cut  for  the 
purpose  of  rapid  hardening  and  impregnation,  sketches  were 
made  of  the  appearance  of  each  section,  with  the  apparently  ab- 
normal parts  distinctly  marked. 

After  complete  hardening,  sectioning,  staining  and  mounting 
of  the  sections  they  were  placed  in  the  Edinger  projection  and 
drawing  apparatus  and  accurate  sketches  made  of  all  appearances. 
The  magnification  was  usually  about  three  to  four  diameters.  On 
each  of  these  drawings  the  scale  was  drawn.  Reductions  of  these 
sketches  are  reproduced. 

The  sections  were  examined  microscopically  by  Dr.  G.  R.  La- 
fora,  and  the  results  of  his  examination  are  noted  on  the  dia- 
grams. Wherever  the  cortex  or  pia  or  fibers  were  diseased  marks 
were  made  on  the  drawings  (Edinger)  and  at  the  same  time  Dr. 
Lafora  marked  the  limits  of  the  so-called  visual  (i.  e.,  calcarine 
type)  cortex  if  these  were  determinable.  At  times  it  was  found 
that  all  distinctive  marks  of  the  calcarine  cortex  had  disappeared 
from  the  lateral  aspect  of  the  hemispheres,  and  at  times  it  was 
even  difficult  to  note  the  limits  along  the  calcarine  fissure.  In 
estimating  the  amount  of  destruction  and  in  drawing  this  on 
the  diagrams  it  was  done  conservatively,  but  on  the  other  hand, 
on  account  of  the  negative  character  of  some  of  the  results,  there 
was  a  liberality  in  defining  the  limits  of  the  calcarine  cortex.  It 
is  possible  that  other  observers  would  have  judged  these  two 
limits  to  be  closer  together  than  they  are  pictured  in  the  accom- 
panying illustrations. 

Following  is  a  summary  of  the  histopathological  findings  by 
Dr.  Lafora :  "The  lesions  of  the  pia  may  be  summarized  as  fol- 
lows :  In  places  where  the  galvano-cautery  acted  directly  upon 
the  pia  (i.  e.,  burned  it)  the  pia  was  found  to  be  completely  des- 
troyed. In  certain  cases  and  in  certain  places  the  following  ef- 
fects of  partial  destruction  were  found :  hemorrhagic  processes 
with  an  accumulation  of  polymorphonuclear  leucocytes  and 
Kornchenzellen  (full  of  pigment  and  fat)  and  a  hyperplasia  of 
the  fibroblasts.  These  are  reactive  processes  consequent  to  a 
partial  destruction  or  to  an  irritation  of  the  pia  a  short  time  pre- 
vious to  the  examination.  A  similar  condition,  though  not  so 
marked,  is  found  in  the  pia  over  a  comparatively  large  area  sur- 


42  SHEPHERD   IVORY  FRANZ 

rounding  the  cauterized  regions,  but  the  pial  alterations  in  the 
latter  cases  are  not  accompanied  by  cortical  changes  as  are  those 
in  the  cauterized  area.  In  the  cerebral  cortex  numerous  patholog- 
ical changes,  especially  different  forms  of  degeneration,  have 
been  found.  When  the  pia  was  totally  destroyed  the  cortex  was 
found  to  have  disappeared,  and  to  be  replaced  by  an  accumulation 
of  blood  cells  with  polymorphonuclear  leucocytes,  around  which 
there  were  many  Kornchenzellen  and  macrophages.  Around  the 
necrotic  zone,  which  sometimes  extended  to  a  considerable  depth 
into  the  white  substance,  was  another  zone  of  a  reactive  charac- 
ter. In  this  secondary  zone  there  were  found  marked  hyperplasia 
of  the  blood  vessels,  many  fibroblasts  showing  a  transformation 
into  macrophages,  and  hyperplasia  of  the  glia  cells.  The  nuclei  of 
the  glia  cells  frequently  showed  karyorrhectic  processes,  and 
these  cells  were  charged  with  pigment,  and  apparently  took  the 
functions  of  the  Kornchenzellen.  When  the  pia  was  only  par- 
tially affected  there  was  produced  a  marked  reactive  process,  in 
which  condition  we  found  very  different  lesions.  At  times  it  was 
found  that  the  zone  agranularis  was  destroyed  and  the  other  cor- 
tical layers  were  only  slightly  affected  by  a  neuroglia  hyperplasia 
and  many  ganglion  cells  showed  tigrolysis  and  neurophagia. 
At  other  times  the  process  was  more  marked  in  the  middle  layers 
of  the  cortex  (granularis  interna  and  ganglionaris  of  Brodmann) 
while  the  zona  agranularis  (lamina  zonalis  of  Brodmann)  and  the 
lamina  pyramidalis  were  not  much  affected.  These  conditions 
are  undoubtedly  dependent  upon  the  different  vascular  destruc- 
tions. In  the  last  described  conditions  in  the  vicinity  of  the 
cortex  in  which  the  lesion  was  pronounced  there  were  always 
found  indications  of  irritative  changes  (neurophagia,  neurog- 
lia hypertrophy  and  hyperplasia),  the  vessels  showed  many  Korn- 
chenzellen in  the  lymphatic  spaces  and  there  were  also  observed 
neuroglic  Stabchenzellen.  We  observed  hemorrhagic,  necrotic 
and  reactive  processes.  Where  hemorrhages  were  produced  a 
reaction  around  these  areas  was  always  found.  Sometimes  the 
obstruction  of  a  vessel  produced  a  necrotic  process  in  the  depth 
of  the  white  substance,  with  a  preservation  of  the  cortex.  In 
the  brains  of  the  animal  operated  upon  by  cutting,  the  degenerat- 
ed elements  (fat  formation)  were  not  well  marked  on  account  of 


POST  MORTEM  EXAMINATIONS  43 

the  short  time  intervening  between  the  operation  and  the  time 
of  the  examination.  In  these  cases,  however,  some  fat  spherules 
were  found,  as  the  drawings  indicate."13 

It  may  be  said  that  the  examinations  of  the  brains  were  made 
after  staining  by  the  methods  of  Nissl  and  Marchi. 

One  point  mentioned  in  Dr.  Lafora's  account  of  the  lesions  is 
worthy  of  special  attention,  viz.,  the  fact  that  in  certain  places 
it  was  found  that  destruction  of  the  pia  was  not  accompanied 
by  destruction  of  all  of  the  underlying  cortex.  In  selecting  the 
cautery  method  of  extirpation  it  was  believed  that  the  burning 
of  the  cortex  with  the  consequent  obliteration  of  the  vessels  would 
produce  an  anemia  of  the  cortex,  and  a  consequent  destruction. 
By  the  use  of  injection  methods  Beevor  (4)  concluded  that  the 
cortex  is  supplied  by  the  arteries  passing  through  from  the  pia.1* 
The  results  of  the  histological  examinations  in  these  cases  appear 
to  indicate  that  not  all  parts  of  the  cortex  are  supplied  by  the 
pial  vessels,  and  that  some  parts  of  the  underlying  white  substance 
may  be  supplied.  Some  of  the  more  interesting,  but  finer  obser- 
vations on  this  point  have  not  been  mentioned  in  the  account  of 
Dr.  Lafora,  but  it  appears  true  that  contrary  to  Beevor's  view 
the  cortex  is  not  entirely  supplied  by  the  pial  arteries.  In  some 
cases,  as  has  been  mentioned  in  the  above  account,  there  has 
been  a  selection  even  in  the  different  layers  of  the  cortex,  and  it 
is  neither  true  that  all  the  cortex  is  destroyed  nor  that  it  may  be 
preserved  entirely. 

13  In  all  the  figures  (except  93  to  96)  indicating  the  conditions  found  by 
microscopical  examination,  dots  are  made  to  indicate  the  location  of  hem- 
morhagic  processes  and  crosses  to  indicate  the  destructions  of  pia,  cortex, 
fibers,  etc.  In  figs.  93  to  96,  the  degeneration  of  masses  of  fibers  could  not 
be  well  shown  by  crosses  and  the  degenerated  bundles  are  shown  by  dots 
and  lines.  The  following  abbreviations  are  used  in  the  figures:  R,  right;  L, 
left ;  calc.  or  calc.  fiss.,  calcarine  fissure ;  cent.,  central  or  Rolandic  fissure ; 
Sylv.,  Sylvian  fissure ;  par.,  parallel  fissure ;  occ.,  occipital  fissure ;  thai., 
thalamus;  lent,  nucl.,  lenticular  nucleus;  vent.,  ventricle;  posterior  (in  figs. 
3°-3S)  indicates  the  posterior  portions  of  the  sections;  c  indicates  the  limits 
of  the  calcarine  type  of  cortex. 

*  "I  hold  with  Duret  that  the  arteries  which  penetrate  and  supply  the 
cortex  are  end  arteries,  and  do  not  anastomose  with  their  contiguous 
branches;  and  I  have  found  that,  if  the  pia  matter  be  carefully  removed,  or 
a  circular  cut  be  made  in  it,  the  subadjacent  cortex  is  not  injected  by  the 
vessels  in  the  surrounding  cortex." 


44  SHEPHERD   IVORY  FRANZ 

RESULTS 

Eight  monkeys  were  used  as  the  subjects  in  this  work. 
These,  as  has  been  said,  had  been  previously  used  in  an 
investigation  on  animal  intelligence  by  Dr.  W.  T.  Shepherd,  and 
in  the  early  work  they  were  given  numerical  designations  instead 
cf  names.  These  numbers  were  adhered  to  in  the  present  work, 
although  they  do  not  conform  with  the  order  in  which  the  obser- 
vations or  the  operations  were  made.  The  following  accounts  of 
the  experiments  are,  however,  given  in  accordance  with  the  ser- 
ial numbers  for  the  purpose  of  convenience. 

An  examination  of  the  case  records  reveals  a  variety  of  opera- 
tions, and  a  variety  of  observations  on  different  aspects  of  mon- 
key intelligence,  some  of  which  can,  and  some  of  which  can  not, 
be  correlated  with  the  brain  conditions. 

Monkey  i.  This  animal  was  trained  to  discriminate  yellow 
(bitter)  from  red  (sweet)  bread.  The  experiments  for  the  pro- 
duction of  the  habit  were  begun  September  23,  and  continued 
over  a  period  of  more  than  two  months  before  an  operation  was 
performed.  In  the  training,  tests  were  made  on  29  days  of  the 
whole  period.  Following  is  an  abbreviated  account  of  the  process 
of  learning:  Sept.  23,  10  tests;  took  yellow  bread  twice  and  the 
other  eight  trials  left  it,  but  always  took  the  red  bread.  Sept. 
24,  10  tests;  similar  result,  except  that  the  monkey  did  not  place 
the  yellow  in  its  mouth  the  second  time  it  picked  it  up.  On  the 
two  succeeding  days  there  was  a  similar  result,  although  on  the 
fourth  day  the  animal  more  often  picked  up  the  yellow  bread.  On 
the  two  succeeding  days  the  monkey  always  picked  up  and  ate  the 
yellow  bread.  On  the  two  succeeding  days  the  monkey  always 
picked  up  and  ate  the  yellow  bread,  and  did  this  apparently  from 
hunger,  although  he  did  not  seem  to  like  the  taste.  On  Sept.  30. 
i  o  tests ;  the  animal  first  showed  perfect  discrimination,  for  it  al- 
ways took  the  red  bread  and  left  the  yellow.  Two  days  later  a 
similar  result  was  obtained,  but  on  Oct.  4,  after  one  day's  rest,  the 
animal  once  more  took  both  the  red  and  the  yellow.  From  this 
time  there  was  a  gradual  curve  of  learning,  with  only  slight  varia- 
tions, to  Oct.  19,  after  which  time  the  monkey  made  very  few. 
mistakes.  On  November  3,  the  animal  performed  the  ten  tests 
satisfactorily,  and  a  rest  of  fifteen  days  was  given,  at  the  end  of 


EXPERIMENTAL  RESULTS  45 

which  time  a  "memory  test"  was  made.  This  latter  showed  per- 
fect retention.  After  five  days  another  series  was  made,  showing 
perfect  retention,  and  again  three  days  later,  Nov.  27,  with  the 
same  result. 

Operation:  November  27,  n  a.  m.  The  occipital  lobes  were 
severed  by  a  cut  posterior  to  the  parieto-occipital  fissure.  During 
the  operation  there  was  little  loss  of  blood  from  the  scalp,  bone 
and  brain,  except  on  the  right  side  where  there  was  considerable 
hemorrhage  when  the  incision  was  made  into  the  brain  substance. 
This  part  of  the  brain  was  compressed  for  about  ten  minutes,  and 
at  that  time  the  blood  flow  ceased.  The  trephine  buttons  were 
inserted,  the  head  was  bandaged,  and  the  animal  was  taken  from 
the  operating  table  at  1 1 130. 

Immediately  after  the  operation  the  eyes  were  widely  dilated, 
and  the  animal  appeared  to  be  only  semi-conscious. 

Two  and  one-half  hours  later  the  animal  was  found  sitting  up 
in  the  cage  in  which  it  had  been  placed,  but  it  was  in  a  huddled 
attitude.  When  a  lump  of  sugar  was  handed  to  it,  it  took  the* 
sugar  but  threw  it  upon  the  floor  of  the  cage.  It  took  a  piece 
of  cotton  wool,  which  had  been  rolled  into  a  swab,  and  threw  it 
upon  the  floor  of  the  cage.  Its  attention  could  be  attracted  easily 
when  noises  were  made,  and  it  started  when  touched  and  when 
the  door  of  the  cage  was  shaken.  When  the  hand  of  the  observer 
was  placed  near  the  cage  netting  the  animal  put  one  of  its  hands 
in  that  direction,  and  at  times  took  hold  of  the  finger.  The 
movements  that  were  made  were  slow  and  indecisive,  and  the 
errors  made  in  putting  its  hands  through  the  wire  netting  were 
from  2.5  to  5  cm.,  i.  e.,  one  to  two  meshes  of  the  netting.  When 
the  gaze  was  attracted  to  an  object  held  in  the  hand  and  a  lump 
of  sugar  was  exposed  in  the  other  hand  of  the  observer,  but  peri- 
pherally to  the  fovea,  the  animal  would  sometimes  turn  to  the 
sugar,  but  most,  if  not  all  the  movements  of  attention  appeared 
to  be  due  to  the  sound  stimuli  rather  than  to  visual  sensations.  In 
one  visual  respect  the  animal  was  quite  unlike  a  normal  animal ; 
it  kept  its  gaze  fixed  on  one  point  for  comparatively  long  periods, 
and  the  quick  shifting  gaze  of  the  normal  animal  was  entirely 
lacking.  When  no  sound  was  made,  and  movements  of  the  ob- 
server were  at  a  minimum  the  animal  remained  absolutely  quiet, 


46  SHEPHERD  IVORY  FRANZ 

the  eyes  became  staring,  the  eyelids  gradually  lowered,  until  the 
eyes  were  covered  almost  completely.  Slight  noises  or  move- 
ments (which  very  likely  produced  noises  although  they  could  not 
be  seen)  waked  the  animal  immediately,  and  there  was  a  return 
to  the  sleepy  condition  immediately  when  quiet  again  reigned. 
The  pupils  were  medium  in  size. 

Thirteen  hours  after  the  operation,  the  animal  was  looked  at; 
when  the  light  was  turned  on  the  animal  came  from  behind  the 
door  of  its  cage,  looked  at  the  observer,  and  appeared  to  be 
bright.  No  special  observations  were  made  at  this  time. 

Thirty-two  hours  after  the  operation,  the  animal  was  with  some 
difficulty  removed  from  its  sleeping  box  to  the  observation  cage. 
Sticks  introduced  into  the  sleeping  box  to  persuade  it  to  change 
its  quarters  were  taken  hold  of  and  twisted  away  from  its  body. 
When  it  went  into  the  observation  box,  it  was  presented  with  a 
lump  of  sugar,  which  it  took  with  a  rather  awkward  movement, 
and  immediately  placed  in  its  mouth.  Several  times  it  took  the 
sugar  from  its  mouth,  held  it  in  its  hand  and  looked  at  it,  and 
returned  it  to  its  mouth  again.  When  the  end  of  a  stick  or  the 
finger  was  put  a  short  distance  through  the  wire  netting  of  the 
cage  the  animal  made  movements  to  take  hold  of  these  things. 
The  movements  were  not  the  quick  lightning-like  movements  that 
a  normal  monkey  makes,  but  slowly  executed  and  inaccurate. 
The  arm  moved  toward  the  goal,  or  rather,  in  the  direction  of 
the  goal,  but  when  the  hand  of  the  animal  was  about  5  to  8 
cm.  away  from  the  object  an  additional  adjustment  was  made  so 
that  the  ringer  or  the  stick  could  be  grasped.  It  was  apparent 
that  the  initial  adjustment  was  very  inaccurate,  that  the  distance 
was  not  properly  sensed,  but  that  the  discrepancy  was  appre- 
ciated, and  that  the  secondary  or  later  adjustment  was  con- 
sidered necessary.  The  actions  of  the  animal  during  these 
tests  could  be  compared  best  to  those  of  a  child  or  even  of 
an  adult  who  tries  to  make  a  new  or  unaccustomed  movement, 
of  a  rather  complex  character,  and  who  attends  to  the  movement 
with  the  eyes  as  a  guide. 

The  indefmiteness  or  impairment  of  the  movement  may  have 
been  due  to  one  or  more  of  several  factors:  (i)  the  loss  of 
rather  definite  visual  sensations  which  are  normally  present  and 


EXPERIMENTAL  RESULTS  47 

important  in  the  adjustment  of  movements;  (2)  to  a  motor  dis-  •" 
turbance;  or  (3)  to  a  loss  of  kinesthetic  sensations  from  the 
eye.  That  there  was  no  motor  disturbance  was  apparent  from 
the  movements  of  a  reflex  character  made  by  the  animal.  The 
bandage  was  apparently  disagreeable,  and  caused  some  irrita- 
tion. At  times  the  animal  put  its  hand  and  plucked  at  the 
bandage  near  the  ear,  pulled  at  it  and  endeavored  to  get  rid 
of  the  irritation.  These  movements  were  performed  accurately, 
quickly,  and  without  the  second  adjustment  which  was  noted 
in  the  case  of  the  movements  of  taking  hold  of  the  finger  or 
of  the  stick. 

The  following  day  the  animal  gradually  improved,  and  it  was 
impossible  for  me  to  determine  any  visual  defect.     The  move-    J 
ments  continued  to  be  a  trifle  uncertain,  but  this  was  all  that 
was  observed  to  be  different  from  a  normal  monkey. 

Two  days  after  the  operation  the  animal  was  tested  with  the 
colored  breads.  In  these  tests,  the  animal  made  no  mistakes, 
although  at  first  the  animal  was  not  as  quick  as  normal,  and 
it  was  usually  necessary  to  wait  a  longer  time  for  the  animal  to 
select  the  bread.  In  the  tests  there  was  no  memory  or  association  ^/ 
loss,  and,  as  far  as  could  be  determined,  the  animal  reacted 
to  the  colors  just  as  it  had  done  previous  to  the  operation. 
After  an  interval  of  a  day  the  animal  was  again  tested  and 
found  to  retain  the  ability  to  discriminate  the  colored  breads, 
and  from  this  time  there  was  no  appreciable  disturbance  in  the 
behavior  of  the  animal.  This  animal  could,  therefore,  see,  and 
there  was  neither  a  visual  disturbance  similar  to  the  permanent 
blindness  noted  by  many  observers,  nor  to  the  temporary  blind- 
ness recorded  by  Ferrier.  Objects  in  all  parts  of  the  field  were 
accurately  seized  and  apparently  discriminated,  and  no  defect  of 
the  nature  of  restriction  of  the  field  of  vision  or  of  a  segmental 
blindness  was  found. 

Four  months  later  a  second  operation  was  performed.  In 
the  intervening  period  the  animal  was  not  practiced  much  on  the 
color  discrimination,  but  sufficient  tests  were  made  with  him 
so  that  this  habit  was  not  forgotten.  No  other  visual  dis- 
criminations were  taught  to  the  animal.  During  part  of  this 
time  the  discrimination  tests  on  the  red  and  yellow  showed  that 


48  SHEPHERD   IVORY  FRANZ 

at  times  the  animal  took  occasionally  the  yellow  piece  of  bread, 
smelled  it,  or  tasted  it  and  sometimes  even  ate  it.  In  a  series 
of  ten  tests  this  was  found  to  occur  but  once,  and  to  be  as  often 
in  the  middle  of  a  series  as  at  the  beginning.  The  animal  was 
well  fed  during  this  period,  and  at  times  refused  to  work  with 
the  colored  breads,  so  that  only  three  to  five  tests  were  made 
on  certain  days.  Following  are  accounts  of  the  color  tests 
immediately  previous  to  the  second  operation: 

March  29,  10  tests:  in  the  second  test  the  monkey  took  the 
yellow  and  the  red  at  one  time  and  placed  both  in  the  mouth 
and  ate  them ;  the  tenth  test  the  animal  did  not  take  either  of  the 
pieces,  although  I  waited  five  minutes;  in  the  other  eight  tests 
the  animal  took  only  the  red  bread  and  this  was  taken  imme- 
diately and  without  hesitation.  March  30:  the  first  seven  tests 
were  made  in  the  usual  manner,  the  animal  taking  the  red  bread 
as  soon  as  the  breads  were  presented;  in  the  eighth  test  the 
animal  took  the  yellow  with  the  left  hand  (in  all  other  tests  the 
animal  had  been  taking  the  bread  with  the  right  hand)  and 
tasted  it,  but  threw  it  away  without  eating;  the  results  of  the 
ninth  test  were  correct,  but  the  monkey  did  not  take  the  red 
bread  on  the  tenth  test  until  after  thirty  seconds.  March  31, 
5  tests :  in  the  first  test  the  animal  took  the  yellow  bread  as 
well  as  the  red,  but  threw  it  away  after  having  tasted  it;  the 
other  four  tests  were  correct.  April  i :  on  the  first  test  the 
animal  took  the  red  bread  and  left  the  yellow,  but  did  not  take 
either  piece  on  the  second  test  and  the  tests 'had  to  be  discon- 
tinued. 

Second  operation,  April  i. — The  trephine  openings  were  made 
farther  back  in  the  skull  so  as  to  expose  the  tip  of  the  occipitals. 
The  buttons  which  had  been  inserted  at  the  time  of  the  first 
operation  were  found  to  be  present,  but  softened  and  adherent 
to  the  dura.  When  they  were  taken  away  there  was  consider- 
able bleeding.  Both  openings  (including  the  two  trephine  open- 
ings on  both  sides)  were  enlarged  with  bone  forceps.  The  dura 
was  cut  to  expose  the  surface  of  the  occipital  areas.  The  cortex 
was  then  burned  with  the  electric  thermo-cautery  at  a  red  heat. 
The  cautery  was  passed  over  the  lateral  aspect  of  the  lobes, 


EXPERIMENTAL  RESULTS  49 

and  inserted  into  the  mesial  part.     The  operation  was  finished 
in  an  hour  (12  130  p.  m.). 

An  hour  and  a  half  after  the  end  of  the  operation  the  animal 
was  inactive  and  appeared  to  be  sleepy.  The  eyes  appeared  to  be 
turned  from  their  normal  positions,  the  left  especially  being 
turned  inwards  and  upwards.  When  a  finger  was  put  through 
the  wire  netting  the  monkey  crouched  back  into  the  corner  of 
the  cage.  When  a  piece  of  bread  was  held  in  front  of  the  cage 
the  monkey  put  its  hand  awkwardly  towards  the  bread,  took 
it  and  conveyed  it  to  the  mouth.  Other  pieces  of  bread  presented 
through  the  wire  netting  were  not  taken.  A  small  piece  of  bread 
dropped  on  the  floor  of  the  cage  was  apparently  seen,  for  it  was 
picked  up  immediately  and  without  hesitation.  A  piece  of  banana 
was  presented  through  the  wire  netting  about  30  cm.  from  the 
animal.  The  left  hand  was  put  forward,  although  the  left  side 
was  farther  from  the  food,  and  the  banana  was  grasped  in  an 
awkward  manner.  Other  pieces  of  food  were  presented  and 
were  sometimes  taken  and  sometimes  not  taken.  When  they 
were  taken  the  movements  were  slow  and  inaccurate.  A  short 
stick  thrust  through  the  netting  did  not  cause  the  animal  to  make 
the  usual  defense  movements  of  grasping  and  shoving,  but  the 
left  hand  was  put  forward  to  take  the  object.  When  the  stick 
was  quietly  inserted  into  the  cage  in  any  direction  the  eyes  of 
the  animal  were  directed  toward  it  when  it  came  sufficiently 
near  (about  15  cm.),  and  although  the  animal  did  not  fight 
against  it  as  a  normal  animal  did,  the  eye  movements  were 
exactly  like  those  of  a  normal  animal.  A  white  dish  containing 
water  was  placed  in  the  cage,  and  the  animal  soon  placed  its 
head  in  the  dish  and  drank.  A  second  attempt  to  drink  was 
more  quickly  made.  It  was  noted  as  peculiar  that  the  monkey 
did  not  use  the  right  hand  for  grasping,  but  used  the  left  which 
performed  the  movements  in  an  uncertain  manner.  Previous  to 
the  operation  this  animal  usually  used  the  right  hand.  At  the 
time  the  notes  were  made  the  following  question  was  inserted : 
How  much  of  the  inaccuracy  in  movement  is  due  to  the  hetero- 
phoria?  This  question  has  not  been  answered  and  even  at  pres- 
ent I  have  no  indication  of  the  part  this  may  have  played  in  the 
motor  inaccuracy.  Throughout  these  observations  the  animal 


50  SHEPHERD   IVORY  FRANZ 

appeared  to  be  under  the  influence  of  the  anesthetic,  to  be  sleepy, 
with  lack  of  energy,  little  attention  and  a  "don't  care"  attitude. 

Twenty-seven  hours  after  the  operation  the  animal  seemed 
perfectly  normal,  except  that  his  movements  were  slow  and  de- 
liberate, and  quite  unlike  the  quick  sharp  movements  of  a  nor- 
mal animal.  Pieces  of  raw  sweet  potato  were  given  to  him ;  these 
he  took  slowly  and  put  into  his  mouth  only  after  having  smelled 
them.  He  ate  them  in  a  normal  manner.  Once  a  piece  of  potato 
was  dropped  on  the  floor  of  his  cage,  he  looked  at  the  food,  then 
at  me  and  reached  for  the  food  which  he  obtained  although  all 
the  time  he  kept  looking  at  me.  Apparently,  the  animal  had 
made  a  judgment  of  the  location  of  the  food,  and  acted  upon 
this  judgment  even  when  the  eyes  were  turned  from  the  food. 
He  drank  water  from  a  dish  apparently  without  difficulty,  and 
picked  up  particles  of  food  from  the  floor  of  the  cage.  When 
a  stick  was  presented  to  him  he  slowly  reached  out  his  hand 
and  took  hold  of  it.  His  attention  was  attracted  by  someone 
in  front  of  the  cage  and  a  stick  was  placed  in  the  back  of  the 
cage,  care  being  taken  to  make  no  noise,  and  when  the  stick 
came  within  the  field  of  vision  he  immediately  turned  and  often 
seized  it.  This  reaction  was  the  same  whether  the  stick  was  to 
the  right  or  to  the  left.  The  angle  of  the  stimulus  was  not 
accurately  determinable,  but  it  appeared  that  the  animal  could 
see  objects  in  the  outer  portion  of  each  field,  i.  e.,  with  the 
nasal  portions  of  the  retinae,  at  least  as  far  away  as  70  to  80 
degrees.  The  angle  of  vision  above  the  head  was  apparently 
normal.  There  was  a  decided  preference  for  the  use  of  the  left 
hand,  but  it  did  not  appear  that  the  right  hand  was  in  any  way 
paralyzed,  although  from  his  continued  use  of  the  left  it  would 
appear  that  there  was  a  paresis  or  some  similar  change  from  the 
normal. 

Three  days  after  the  operation  the  animal  appeared  the  same 
as  that  just  noted.  On  this  day,  five  tests  with  the  colored 
breads  were  made.  On  the  first,  second  and  fifth  the  monkey 
took  only  the  red  bread,  but  on  the  third  and  fourth  tests  took 
both  yellow  and  red.  Two  days  later,  five  tests  were  correct. 
The  animal  was  exhibited  before  the  Georgetown  Clinical  So- 
ciety on  April  4,  and  at  that  meeting  the  members  were  unable 


EXPERIMENTAL  RESULTS  51 

to  note  any  difference  from  the  normal.  From  the  results  of 
the  bread  tests  it  was  apparent  that  the  animal  retained  the 
ability  to  discriminate  colors,  and  although  the  tests  on  the  third 
day  after  the  operation  were  not  entirely  successful,  they  were 
quite  as  successful  as  they  had  been  immediately  previous  to 
the  operation. 

Nine  days  after  the  operation  (April  10),  it  was  noted  that 
the  animal  was  not  inclined  to  work.  It  did  not  eat.  During  the 
night  of  the  Qth  the  animal  tore  the  bandage  from  the  head, 
and  opened  the  scalp  wound  slightly.  On  the  following  day 
the  scalp  was  swollen,  and  the  brain  appeared  to  be  bulging 
through  the  trephine  openings.  The  animal  did  not  work  on 
the  tests,  and,  as  it  refused  to  eat,  no  observations  of  vision  or  of 
movement  were  possible.  At  8  p.  m.  of  this  day  the  animal  was 
found  to  be  quite  stupid  and  dull.  It  took  a  long  time  and  a 
violent  stimulus  to  arouse  him.  At  one  time  the  eyes  were 
rolled  upwards  and  showed  a  slight  nystagmic  movement.  At 
another  time  there  were  twitchings  of  the  hand.  The  animal 


FIGS.  10,  ii,  12  and  13.  Monkey  i.  Lateral  and  mesial  aspects  of  the  cere- 
bral hemispheres,  showing  the  parts  destroyed  by  the  operation.  The  latter 
is  a  reconstruction.  Slightly  reduced  (cf.  scale).  Traced  from  photograph. 
The  small  size  numerals  are  the  sections  from  which  other  figures  (14-23) 
were  drawn. 


SHEPHERD  IVORY  FRANZ 


was  killed  with  chloroform  at  9:30,  and  the  autopsy  was  per- 
formed immediately. 

At  the  autopsy  the  scalp  in  the  neighborhood  of  the  operative 


tent 


FIGS.  14  and  15.  Monkey  I.  Gross  sections  of  the  hemispheres,  showing 
the  parts  affected  by  the  operations.  About  natural  size.  Drawn  at  time  of 
autopsy,  free  hand.  The  illustrations  are  taken  from  the  lower  surfaces  of 
the  sections  indicated  by  lines  in  figs.  10-13. 


EXPERIMENTAL  RESULTS 


53 


cuts  was  found  to  be  swollen,  the  cellular  tissue  was  rilled  with 
a  watery  fluid  which  could  be  squeezed  from  it.  The  scalp  at 
this  place  was  about  a  half  centimeter  thick.  The  brain  bulged 
through  the  trephine  openings.  The  dura  was  adherent  to  the 
brain  and  the  scalp  was  adherent  to  the  dura.  The  brain  was 
removed  from  the  skull  with  difficulty.  The  posterior  surfaces 
of  the  hemispheres  were  much  reddened  and  soft  to  the  touch; 
there  was  no  appearance  of  pus.  The  brain  was  placed  in  toto 
in  95  per  cent  alcohol.  The  photographs  were  made  thirty- 
six  hours  after  the  autopsy. 

Figures  10  to  23  show  the  brain  with  the  effects  of  the  two 
operations.  In  figs.  10,  n,  12  and  13  are  given  diagrams 
of  the  lateral  and  mesial  aspects  of  the  hemispheres,  with  the 
parts  of  the  cortex  destroyed  at  the  time  of  the  second  opera- 


FIGS.  16,  17,  18,  19,  20,  21,  22  and  23.  Monkey  I.  Horizontal  sections 
through  the  occipital  parts  of  the  cerebral  hemispheres,  showing  effects  on 
cortex,  and  underlying  fibers  of  the  second  operation.  About  3/2  natural 
size.  Edinger  drawing  apparatus. 

tion.  Figs.  14  and  15  show  the  gross  appearance  of  the  sections 
made  for  the  purpose  of  microscopical  study,  with  the  parts 
marked  thereon  where  the  cortex  had  been  destroyed.  The  cor- 


54  SHEPHERD   IVORY  FRANZ 

tical  effects  of  the  first  operation  are  not  indicated,  and  it  was 
impossible  to  differentiate  these  from  the  results  of  the  second 
operation.  Figs.  16,  17,  18,  19,  20,  21,  22  and  23  give  the  appear- 
ance of  the  microscopical  sections,  which  were  stained  by  the 
Nissl  method,  and  which  show  the  hemorrhagic  and  cortical  ef- 
fects of  the  second  operation.  It  will  be  noted  that  the  sections 
numbered  in  figures  10  to  15  correspond  with  the  sections 
marked  with  the  same  numbers  in  figures  16  to  23.  The  areas 
of  cortical  destruction  (marked  black)  in  figs.  10-15  have  been 
drawn  from  the  examinations  of  the  microscopical  sections. 

The  results  of  the  examinations  of  the  microscopical  sections 
are  given  by  Dr.  Laf ora  as  follows :  "Monkey  i ,  cauterization 
of  the  brain,  Nissl  method,  horizontal  sections.  On  the  right 
side  the  occipital  lobe  lateral  aspect  is  almost  entirely  de- 
stroyed, the  lesion  involving  the  whole  depth  of  this  part  of 
the  cortex.  A  part  of  the  periphery  of  the  calcarine  type  of  cor- 
tex escaped  destruction,  and  the  calcarine  fissure  is  affected  only 
in  its  posterior  ramification,  especially  the  superior  part.  On 
the  left  side  the  lesion  is  more  extensive  than  on  the  right,  the 
calcarine  type  of  cortex  being  more  affected  especially  in  the 
superior  part  of  the  occipital  pole.  The  vessel  lesions  have  pro- 
duced softenings  in  the  white  matter  which  interfered  with  the 
fibers  coming  to  the  visual  cortex.  The  anterior  part  of  the 
calcarine  fissure,  and  some  parts  of  the  posterior  are  well  pre- 
served." 

Monkey  2.  This  animal  was  trained  to  discriminate  the  four 
colors.  Red  and  blue  were  sweet  and  green  and  yellow  were 
bitter.  The  training  experiments  began  October  20.  There  was 
a  gradual  acquisition  of  the  habit  of  taking  the  red  and  blue 
and  of  leaving  the  green  and  yellow,  which  became  perfected 
^after  this  date  there  were  no  wrong  reactions  as  long  as  the 
animal  was  in  a  normal  condition)  after  six  days.  The  tests  were 
continued,  however,  a  month  longer,  with  intervals  in  which  the 
memory  was  tested.  The  final  tests  were  made  on  December  i, 
the  day  of  the  operation,  and  on  this  day  the  animal  made  no 
mistakes  in  ten  trials. 

Operation,  December  i.  The  usual  preliminary  parts  of  the 
operation  were  performed  in  the  manner  described.  On  account 


EXPERIMENTAL  RESULTS  55 

of  the  fact  that  previous  sections  of  the  brains  of  other  animals 
had  not  been  followed  by  visual  disturbances  of  sufficient  amount 
to  be  noticeable,  if  they  were  present,  I  made  the  incision  in  the 
brain  much  anterior  to  the  so-called  visual  cortex,  so  that  as 
much  of  the  occipital  pole  as  possible  should  be  included  in  the 
effects  of  the  operation.  It  was  intended  to  separate  completely 
the  occipital  lobes  from  the  frontal  parts  of  the  hemispheres, 
but  on  account  of  the  depth  of  the  brain  at  the  point  the  knife 
was  inserted,  all  was  not  cut  away,  as  was  later  learned  at  the 
time  of  the  autopsy  and  at  the  time  of  the  microscopical  examina- 
tion. 

About  fifteen  minutes  after  the  operation  was  completed  the 
animal  staggered  drunkenly  against  the  sides  of  the  cage  in  which 
he  had  been  placed.  When  a  sudden  noise  was  made  he  did  not 
jump.  The  pupils  were  widely  dilated,  and  there  were  slight 
tremors  of  the  eyelids. 

Twenty-four  hours  after  the  operation,  the  animal  was  fourrd 
to  be  fairly  active,  engaged  chiefly  in  pawing  at  the  floor  of 
the  cage  and  scratching  at  the  bandage  on  his  head.  A  ringer  of 
the  experimenter  poked  through  the  wire  of  the  cage  elicited  "&t 
times  a  slapping  of  the  floor,  at  other  times  it  appeared  that  no  at- 
tention was  paid  to  it,  activity  at  least  not  being  directed  toward 
the  finger.  A  piece  of  rubber  tubing  hung  through  the  top  of 
the  cage  elicited  no  reaction  until  the  animal  was  touched,  when 
he  made  a  slap  in  that  direction.  Water  was  presented  in  a 
saucer.  The  animal  put  out  his  paw  to  investigate,  got  it  in  the 
water,  then  leaned  over  and  drank.  A  prune  was  held  outside 
but  near  the  wire  of  the  cage.  The  monkey  started  to  put  out 
his  hand  to  grasp  it,  but  struck  the  wire  and  did  not  persist. 
Later  the  prune  was  held  in  this  position  again  and  the  paw 
was  put  out  and  grasped  the  prune  accurately.  A  prune  was 
thrown  upon  the  floor;  three  grabs  were  made  in  the  general 
direction  of  the  prune  and  each  time  the  monkey  missed  it  by 
about  7  cm.  It  desisted.  On  the  following  day  he  groped  about 
the  cage,  especially  on  the  floor  when  any  noise  was  made,  and 
did  not  'reach  for  objects  held  in  front  of  him,  but  gave  some 
reactions  to  things  that  were  held  above  the  eyes.  It  seemed 
at  times  that  he  saw  things  held  in  the  upper  part  of  the  visual 


56  SHEPHERD   IVORY  FRANZ 

field.  This  was  not  clear,  however,  for  at  times  he  would  not  pay 
any  attention  to  the  food.  When  a  stick  was  held  close  to  him,  he 
paid  no  attention  to  it  as  he  had  previously  done,  and  there  were 
no  defense  movements  to  push  away  the  stick.  Only  when  the 
food  was  placed  near  the  nose  or  mouth  did  he  make  definite  at- 
tempts to  grasp  it,  and  at  times  it  appeared  that  his  reactions  were 
due  more  to  smell  stimuli  than  to  visual  ones. 

Three  days  after  the  operation  he  was  placed  in  the  large 
observation  cage  into  which  he  went  from  the  small  living  box, 
almost  as  soon  as  the  door  of  the  latter  was  opened.  A  peanut 
held  at  the  netting  of  the  cage,  about  25  cm.  away  from  his 
head  was  well  grasped  and  the  movement  was  quickly  executed. 
No  hesitation  was  observed  at  this  time.  A  dish  of  water  was 
placed  on  the  floor  of  the  cage  about  54  cm.  from  where  he 
was  sitting;  the  animal  immediately  went  to  it,  drank  from  it 
in  an  apparently  normal  manner,  and  went  back  to  his  old  sitting 
position.  Other  food  was  placed  outside  of  the  cage  but  within 
reach  of  his  extended  paw,  and  these  pieces  he  took  and  ate. 
Small  pieces  of  food  on  the  floor  of  the  cage  were  taken  in  an 
apparently  normal  manner,  and  the  sawdust  on  the  floor  of  the 
cage  was  picked  over  for  particles  of  food.  A  stick  inserted 
in  the  cage  was  promptly  seized,  and  warded  off.  The  animal 
moved  its  eyes  in  an  apparently  normal  manner,  and  the  eyes 
followed  a  moving  person.  The  animal  turned  its  eyes  toward 
anyone  entering  the  room.  It  moved  from  the  large  cage  to- 
the  small  one  and  reversely  without  mistakes  regarding  doors, 
etc.,  and  in  this  respect  also  appeared  to  be  able  to  differentiate 
visual  stimuli. 

Four  hours  later  the  animal  seemed  visually  like  a  normal 
animal.  It  took  food,  drank  water,  and  put  its  hand  through 
the  cage  to  get  materials  outside.  At  times  its  movements  were 
not  as  accurately  coordinated  as  in  a  normal  animal  but  the 
errors  of  movement  were  not  large  and  on  this  point  it  was  im- 
possible to  make  any  accurate  judgment.  The  animal  scratched 
the  bandage  almost  continually  and  it  was  thought  that  perhaps 
there  was  some  pus  formation  at  the  wound.  For  this  reason 
the  animal  was  lightly  anesthetized,  the  old  bandage  taken  off, 
and  a  new  one  adjusted.  The  wound  seemed  to  be  in  a  perfectly 


EXPERIMENTAL  RESULTS  57 

healthy  condition,  and  to  be  uniting  by  first  intention.  A  wet 
compress  of  2  per  cent  carbolic  acid  was  placed  on  the  head 
over  the  wound.  The  animal  recovered  from  the  anesthetic  in 
about  an  hour.  The  animal  moved  from  the  small  cage  to  the 
burlap  bag  without  any  difficulty  and  apparently  knew  what  it 
was  doing. 

On  this  day  and  on  the  succeeding  days,  the  animal  appeared 
to  have  perfect  vision  and  to  be  able  to  coordinate  the  visual  im- 
pressions with  the  proper  movements.  At  no  time  after  the 
first  days  was  I  able  to  determine  any  defect  of  vision,  and  this 
was  also  shown  in  the  tests  with  the  colored  breads.  Two  days 
after  the  operation  the  animal  made  some  mistakes  with  the 
colors.  In  all  of  the  ten  tests  made  on  that  day  the  animal  took 
the  yellow  bread  and  smelled  of  it.  Once  a  piece  of  green  bread 
was  taken  in  the  same  grab  with  a  red,  and  this  was  apparently 
due  to  the  fact  that  they  were  very  close  to  each  other  on  the 
plate.  On  the  following  day,  the  monkey  made  no  mistakes  in 
the  color  tests,  and  it  seemed  most  likely  that  the  mistakes  made 
on  the  previous  day  were  not  due  to  a  lack  of  discrimination. 
It  is  particularly  worthy  of  notice  that  in  one  of  the  tests  the 
piece  of  blue  bread  fell  from  his  hand  and  that  he  immediately 
picked  it  up,  rather  than  take  one  of  the  other  (yellow  and  green) 
pieces  remaining  on  the  plate.  The  observations,  and  also  the 
tests,  indicated  that  if  there  had  been  any  visual  defect,  it  was 
of  a  nature  similar  to  those  observed  by  Ferrier.  The  general 
reactions  of  the  animal  were,  however,  so  abnormal  for  a  day 
following  the  operation,  that  I  think  we  are  not  justified  in 
concluding  that  the  defect  is  visual  and  is  of  any  special  char- 
acter, but  I  believe  we  should  conclude  that  the  disturbance  was 
a  general  one,  and  is  to  be  compared  with  the  shock  effects  of 
operations  such  as  are  exhibited  by  man,  especially  after  opera- 
tions on  the  nervous  system. 

The  animal  was  killed  with  chloroform,  December  5.  The 
autopsy  was  performed  immediately  after  death.  The  brain  ap- 
peared to  be  normal  except  at  the  points  where  the  knife  had 
been  inserted,  and  there  was  no  oedema  apparent  to  the  eye. 
The  brain  was  placed  in  alcohol  and  photographed  and  weighed 


58  SHEPHERD   IVORY  FRANZ 

twenty-four  hours  after  the  autopsy.     The  brain  weighed  85 
grams. 

Figures  24  to  35  show  the  conditions  that  were  found  post 
mortem.  In  figs.  24,  25,  26  and  27,  the  tracings  from  the  photo- 
graphs, there  are  shown  the  points  of  insertion  of  the  knife,  and 
the  sections  made  for  the  purpose  of  examination  by  histological 
methods.  At  the  time  the  gross  sections  were  made,  drawings 
were  made  of  the  appearances  of  the  sections  and  these  are 


FIGS.  24,  25,  26  and  27.  Monkey  2.  Lateral  and  mesial  aspects  of  the  cere- 
bral hemispheres,  showing  the  course  of  the  knife  cuts  into  the  brain  x — jrt 
and  y — yt  and  the  location  of  the  parts  of  the  brain  examined  histologically. 
Slightly  reduced  (cf.  scale).  Traced  from  photographs. 

given  in  figs.  28  and  29.  From  these  drawings  and  from  a  care- 
ful comparison  of  the  brain  as  a  whole  and  in  the  sections,  a 
reconstruction  of  the  course  of  the  knife  cuts  has  been  made 
and  these  are  indicated  in  figs.  24-27,  by  the  heavily  dotted  lines. 
It  will  be  seen  that  the  knife  was  inserted  just  posterior  to  the 
central  fissure  and  that  in  its  course  it  cut  away  a  large  part  of 
the  occipitals  from  the  anterior  part  of  the  hemispheres,  but 
that  the  lower,  especially  the  temporal,  portions  of  the  brain 


EXPERIMENTAL  RESULTS 


59 


escaped.     The  microscopical  examinations  of  the  sections  are 
illustrated  in  figs.  30-35. 

The  account  of  the  histological  examination  by  Dr.  Lafora  is 


Cenh 


FIGS.  28  and  29.  Monkey  2.  Sections  of  the  cerebral  hemispheres  showing 
the  hemorrhages  due  to  the  sections  of  the  brain,  and  the  parts  probably 
affected  by  the  operation.  About  natural  size.  Drawn  free  hand  at  time  of 
autopsy.  The  illustrations  are  the  appearances  of  the  lower  surfaces  of  the 
sections  indicated  in  figs.  24-27. 


6o 


SHEPHERD   IVORY  FRANZ 


as  follows:  "The  sections  were  prepared  by  the  method  of 
Nissl  by  Dr.  Achucarro.  On  both  sides  of  the  brain  the  sections 
show  the  lesions  produced  by  the  knife,  which  seem  to  be  very 
extensive  in  its  transverse  directions.  Although  we  are  unable 
to  judge  of  the  amount  of  the  fibers  which  were  cut  by  the 
operation  on  account  of  the  histological  method  used  in  the  ex- 
amination, it  is  sure  that  most  of  the  optic  fibers,  except  those 
lying  low  in  the  cerebrum,  were  destroyed  or  at  least  affected 
by  the  section.  The  cortex  shows  some  reactive  processes  of 
the  neuroglia  and  of  the  ganglion  cells  some  of  which  later 
show  a  slight  degree  of  tigrolysis.  In  the  inferior  part  of  the 
white  matter  the  lesion  is  not  as  extensive  as  in  the  middle  part. 
The  drawings  indicate  the  general  extent  of  the  lesions." 


post 


FIGS.  30,  31,  32,  33,  34  and  35.  Monkey  2.  Horizontal  sections  through  the 
lesions  indicated  in  figures  24-27.  About  3/2  size.  Edinger  drawing 
apparatus. 

Monkey  5.  This  animal  had  been  trained  on  the  discrimination 
of  the  large  and  small  pieces  of  bread.  The  experiments  for  the 
production  of  this  habit  were  sporadically  done,  but  the  sys- 
tematic training  for  the  present  paper  was  not  undertaken  until 
about  two  weeks  before  the  operation.  Following  is  an  account 
of  the  process  of  learning  at  that  time : 

September  5,   10  tests:  only  once  ate  both  large  and  small 


EXPERIMENTAL  RESULTS  61 

pieces,  viz.,  first  trial;  on  the  first,  second,  third  and  fifth  trials, 
she  took  the  large  before  the  small,  and  on  the  ninth  and  tenth  the 
large  after  the  small.  After  the  first  trial,  however,  the  animal 
did  not  eat  the  large  piece,  but  smelled  or  tasted  it  and  threw  it 
away.  September  6,  10  tests:  took  the  large  piece  on  the  first, 
sixth  and  on  the  eighth  trials,  but  ate  the  large  piece  only  the 
first  two  times.  September  9,  20  tests :  took  the  large  piece  only 
the  first  two  times.  September  10,  5  tests:  took  both  pieces  the 
first  three  trials,  but  the  smaller  piece  only  on  the  fourth  and 
fifth  trials.  September  n,  20  tests:  first,  took  both  pieces  but 
did  not  eat  larger;  from  second  to  twentieth  only  smaller.  Sep- 
tember 14,  20  tests:  on  the  first  and  second  trials  she  took  only 
the  small  pieces,  but  from  the  third  to  the  fifth  the  larger  ones 
were  also  taken,  although  they  were  only  tasted,  not  eaten.  Sep- 
tember 15,  10  tests:  only  the  small  were  taken.  September  i6? 
10  tests:  only  the  small  were  taken.  September  17,  5  tests:  only 
the  small  were  taken.  These  tests  were  the  final  ones  before 
the  operation  which  was  begun  an  hour  later. 

Operation,  September  17,  10  a.  m.  Occipital  lobes  were  cau- 
terized. There  was  considerable  hemorrhage  which  was  checke  1 
by  hot  compresses  to  the  brain.  Immediately  after  the  comple- 
tion of  the  operation  the  face  of  the  animal  was  cyanotic,  the 
eyelids  closed,  and  the  facial  muscles  were  contracted  into  a 
grimace  (Schnauzkrampf).  The  left  pupil  was  about  one  and 
one  half  times  larger  than  the  right,  and  neither  reacted  to  light. 
The  head  was  turned  backwards  and  towards  the  left;  the  right 
arm  was  flexed  at  the  elbow  and  the  left  arm  was  extended ; 
both  legs  were  extended.  There  was  hypertonia,  more  marked 
on  the  left. 

About  three  minutes  later  the  left  arm  became  flexed  at  both 
shoulder  and  elbow  and  the  left  leg  at  the  thigh;  the  flexion 
of  the  left  arm  at  this  time  was  greater  than  the  flexion  of  the 
right  arm  noted  immediately  after  the  operation  and  which  had 
continued.  When  the  animal  was  placed  on  its  back  or  on  the 
right  side  there  was  a  tendency  to  turn  to  the  left,  and  the  trunk 
of  the  animal  described  an  arc  with  the  concavity  towards  tht 
left  (emprosthotonus).  The  tongue  was  protruded,  and  devi- 
ated to  the  left ;  when  it  was  pushed  into  the  mouth  and  towards 


62  SHEPHERD   IVORY  FRANZ 

the  right,  it  gradually  returned  to  the  protruded  left  position. 
Ten  minutes  after  the  operation  was  finished  it  was  found  that 
both  sides  of  the  animal  were  approximately  equally  flexed,  and 
the  tail  was  turned  under  the  body  but  in  the  median  line.  The 
animal  was  tremulous;  it  was  placed  close  to  the  fire  and  the 
tremor  (shivering)  ceased  in  about  two  minutes. 

About  half  an  hour  after  the  operation  the  animal  attempted 
to  sit  up,  but  immediately  fell  down,  and  remained  in  a  rather 
unnatural  attitude.  Two  hours  after  the  operation  it  was  found 
sitting  up,  and  when  I  moved  about  the  room  it  followed  with 
its  head  and  eyes  all  my  movements ;  part  of  this  may  have  been 
due  to  the  noise  made  by  me  in  walking,  but  the  movements 
of  the  animal  appeared  to  be  rather  those  associated  with  vision. 

Eight  hours  after  the  operation,  the  animal  was  sitting  in  its 
cage  in  a  perfectly  normal  attitude.  The  contractions  of  the 
groups  of  muscles  had  entirely  disappeared,  and,  so  far  as  could 
be  determined,  the  movements  were  normal  in  character,  but 
rather  slow.  Four  pieces  of  bread  were  placed  approximately 
5  cm.  apart  on  the  floor  of  the  cage  in  the  form  of  an  arc, 
30  cm.  away  from  the  eyes;  for  about  ten  seconds  the  animal 
took  no  notice  of  the  food  (it  had  not  been  fed  on  this  day 
except  at  the  time  of  making  the  final  five  tests  on  the  dis- 
crimination of  large  and  small)  but  finally  accurately  reached 
for  and  obtained  one  of  the  pieces  in  the  middle;  after  it  had 
eaten  this  piece  it  took  the  second  middle  piece,  but  during  ten 
minutes  it  disregarded  the  other  two  pieces  which  were  at  the 
ends.  Some  pieces  of  apple  were  dropped  into  the  cage;  some 
of  these  the  animal  picked  up  with  a  great  degree  of  accuracy, 
but  the  movements  were  slow  and  it  did  not  immediately  try  to 
secure  the  food.  At  times  the  food  was  disregarded  until 
some  part  of  the  animal,  a  hand  or  a  foot,  touched  one  of  the 
pieces,  whereupon  she  reached  to  the  appropriate  spot,  secured 
the  piece  and  inserted  it  in  the  mouth.  A  fresh  fig  was  placed  in 
the  cage  about  45  cm.  distant  from  the  eyes  of  the  animal.  This 
it  disregarded  until  it  was  shoved  near  enough  to  the  animal  to 
be  touched  by  it,  whereupon  the  animal  took  the  fig  and  ate  half 
of  it.  After  this  she  wandered  around  the  cage  picking  up  pieces 
here  and  there,  but  at  other  times  her  attention  was  attracted  to 


EXPERIMENTAL  RESULTS  63 

the  pieces  of  food  solely  by  the  sight,  and  at  times  it  appeared 
that  the  animal  did  not  see  but  picked  up  the  food  only  when  it 
was  accidently  touched  by  part  of  the  body.  Tests  for  deter- 
mining the  extent  of  the  visual  field  were  unsuccessful,  for  the 
animal  did  not  respond  to  the  food  when  it  was  offered  on 
the  wires.  The  latter  observations  were  made  at  night  in  arti- 
ficial, but  good  light,  and  it  is  possible  that  the  shadows  thrown 
by  the  food  on  the  wires  and  the  shadow  of  the  cage  on  the  food 
were  distracting,  although  I  lay  no  stress  on  this  point.  During 
all  the  tests  mentioned  in  this  paragraph  the  right  eye  of  the  ani- 
mal was  much  inflamed,  probably  due  to  the  anesthetic. 

Twenty-four  hours  after  the  operation  the  animal  was  ob- 
served and  tested  by  Dr.  Lafora,  who  made  the  following  notes : 
"The  right  eyelid  is  much  inflamed,  but  the  eye  is  kept  open,  and 
is  used  with  the  other;  the  pupils  react  equally  to  light.  Objects 
(food)  at  some  distance  (about  60  cm.)  were  at  first  not  at- 
tended to  and  it  appeared  that  the  animal  could  not  see  them; 
only  when  pieces  were  brought  near  its  face  did  it  try  to  take 
them.  In  a  number  of  tests  she  continued  to  make  movements 
as  if  to  take  other  pieces  of  food  in  the  same  place  although 
none  were  being  presented ;  at  other  times  the  animal  would  look 
directly  at  the  places  and  moved  her  head  and  eyes  as  if  to 
follow  the  movements  of  the  (imaginary)  particles  of  food.  Is 
this  a  perseveration  phenomenon?  Small  objects,  such  as  wires, 
were  not  well  discriminated,  for  the  animal  frequently  made  no 
movement  until  the  wires  were  close  to,  sometimes  touching, 
the  face  or  the  facial  hairs;  similarly  with  small  pieces  of  apple. 
The  first  experiments  on  the  field  of  vision  indicated  that  the 
monkey  did  not  have  a  normally  fine  perception  in  the  macula, 
for  objects  about  40  cm.  away  were  peered  at  and  the  animal 
moved  the  head  closer  as  if  to  get  a  better  view  before  attempt- 
ing to  take  them.  All  objects  held  towards  the  periphery  were 
seen  but  the  movements  of  grasping  were  not  accurate.  It  is  a 
remarkable  fact,  however,  that  the  animal  looked  at  a  fly  at 
the  bottom  of  the  cage  and  followed  its  movements  with  head 
and  eyes.  A  piece  of  an  apple  was  afterwards  held  on  a  wire 
in  front  of  the  animal  and  moved  about  far  and  near  and  to 
the  right  and  left.  The  animal  apparently  centered  its  attention 


64  SHEPHERD   IVORY  FRANZ 

upon  the  object  which  it  approached  and  obtained  after  some 
unsuccessful  attempts.  After  the  monkey  found  it  impossible  to 
obtain  some  moving  pieces  of  food  by  grasping  with  the  hand, 
the  animal  moved  the  head  towards  the  food  and  took  it  directly 
into  the  mouth.  Pieces  of  food  held  to  the  right  or  to  the  left 
brought  about  approximately  normal  movements  of  the  animal, 
except  when  the  food  was  held  at  the  extreme  right,  where  it 
was  found  that  movements  were  sometimes  produced  but  only 
after  a  much  longer  time  than  when  the  food  was  held  in  any 
other  part  of  the  field.  The  hallucinatory  tendency,  noted  above, 
to  take  objects  not  presented  was  again  shown  in  the  later  move- 
ments ;  at  times  when  pieces  of  food  had  not  been  presented  for  a 
minute  or  two,  the  animal  grasped  in  the  air  or  groped  on  the 
floor  in  the  location  of  previously  obtained  food;  this  would 
indicate  that  the  visual  part  of  the  reaction  is  not  a  perservation 
but  an  hallucinatory  phenomenon.  Color  discrimination  ap- 
peared to  be  preserved,  at  least  to  some  degree,  for  the  animal 
selected  tomato  three  times  instead  of  apple,  its  normal  prefer- 
ence being  for  the  former.  In  the  later  experiments  the  move- 
ments of  grasping  were  accurate,  showing  a  complete  associa- 
tion between  the  movements  of  the  hand  and  arm  and  the  visuo- 
kinetic  representation  of  the  movement.  A  piece  of  cotton  soaked 
in  alcohol  and  then  lighted  was  brought  close  to  the  animal  and 
this  experiment  many  times  repeated  showed  that  there  was  an 
ability  on  the  part  of  the  animal  to  see  with  all  parts  of  the 
retina,  on  the  right  as  well  as  on  the  left,  the  movements  in  all 
parts  of  the  field  being  accurate  and  quick.  When  one  piece  of 
lighted  cotton  was  shown  and  held  the  attention  of  the  animal, 
and  a  second  piece  was  brought  inwards  from  the  sides  (right 
and  left)  the  animal  turned  towards  the  second  piece,  showing 
that  the  extent  of  the  field  was  approximately  normal.  Conclu- 
sions :  Diminution  of  visual  acuity ;  no  diminution  in  extent  of 
the  visual  field,  at  least  at  the  sides,  although  it  is  impossible  on 
account  of  the  eye  movements  to  determine  whether  or  not  there 
is  a  central  scotoma;  ability  to  discriminate  colors  appears  to  be 
preserved;  and  there  is  exact  visuo-kinetic  representation." 

On  the  third  day  after  the  operation  the  animal  was  tested  with 
large  and  small  pieces  of  bread ;  on  the  first  trial  she  selected  the 


EXPERIMENTAL  RESULTS  65 

small  piece  and  disregarded  the  large ;  on  the  second  trial  she  took 
the  large  piece  tasted  it  and  .threw  it  away  and  then  took  the 
small  piece  which  she  ate;  the  third  trial  was  a  repetition  of  the 
second ;  on  the  fourth  trial  she  took  only  the  small  piece ;  and  on 
the  fifth  trial  she  got  both  pieces  in  one  grasp  and  ate  the  small. 
The  results  of  these  experiments  do  not  indicate  plainly  whether 
or  not  the  habit  of  discrimination  of  the  large  and  small  pieces 
persisted,  but  the  indications  are  that  the  habit  remained,  because 
each  of  the  two  times  that  the  animal  obtained  the  smaller  piece 
she  did  not  try  to  take  the  larger  one  which  remained  on  the 
glass  plate,  and  each  of  the  two  times  that  she  obtained  the  larger 
piece  first  she  returned  to  the  plate  and  secured  the  smaller  piece. 
In  these  experiments  she  showed  the  condition  noted  in  the  other 
tests  on  this  day,  viz.,  a  certain  amount  of  inaccuracy  in  motor 
adjustment.  The  taking  of  the  larger  piece  in  the  fifth  trial  was 
awkwardly  done,  and  the  taking  of  both  pieces  in  the  second  and 
third  trials  may  have  been  due  to  this  motor  derangement.  A 
piece  of  raw  potato  was  dropped  on  the  floor  of  the  room  close 
to  the  cage,  about  75  cm.  from  the  animal;  she  moved  to  the 
front  of  the  cage,  accurately  reached  under  the  bottom  bar  and 
secured  the  piece  of  food.  A  piece  of  raw  apple  was  held  on  a 
wire  about  20  cm.  from  the  eyes  of  the  animal,  and  midway  be- 
tween them;  this  she  grasped  on  the  second 'attempt  after  having 
made  at  first  an  error  of  2  cm.  After  having  obtained  the  piece 
of  apple  she  grasped  in  the  same  direction  (or  place)  although 
there  was  no  food  being  presented,  and  her  actions  at  this  time 
gave  me  the  same  impression  as  they  did  Dr.  Lafora  on  the  pre- 
ceding day,  viz.,  that  there  was  an  hallucination  or  a  persistence 
of  the  impression.  A  piece  of  raw  potato  held  in  front  of  the 
animal  about  30  cm.  away  was  reached  for;  in  grasping  for  it 
the  animal  made  a  movement  error  of  about  7  cm.  at  first  but 
on  the  second  attempt  secured  the  food.  A  fly  was  walking  over 
the  back  of  the  cage  about  60  cm.  from  the  monkey  and  to  the 
left ;  the  animal  moved  cautiously  toward  the  part  of  the  cage 
where  the  fly  was  and  when  near  enough  she  grasped  for  it  with 
the  left  hand,  hitting  the  spot  where  the  fly  had  been  (the  fly 
flying  away  when  the  hand  approached ) .  A  piece  of  raw  carrot 
was  dropped  into  the  cage,  but  fell  outside :  the  animal  groped  at 


66  SHEPHERD   IVORY  FRANZ 

the  place  where  the  carrot  fell,  moved  to  the  other  end  of  the 
cage,  returned  to  its  original  position  in  about  ten  seconds,  and 
picked  up  a  piece  of  raw  potato;  then  it  put  its  hand  outside  the 
cage  and  picked  up  the  carrot  accurately  and  without  hesitation. 
A  piece  of  apple  and  a  piece  of  potato  were  placed  on  the  floor 
of  the  cage  about  75  cm.  away  from  the  animal;  by  short  steps 
she  moved  in  the  direction  of  the  food  and  when  sufficiently  near 
reached  accurately  for  and  obtained  the  potato  but  disregarded 
the  apple  which  was  on  the  right.  Nine  small  pieces  of  food, 
three  each  of  raw  carrot,  apple  and  potato,  were  dropped  into  the 
cage  from  .the  top,  a  few  rolling  outside  and  the  distribution  in 
the  cage  being  irregular,  the  monkey  took  immediately  two  pieces 
which  were  within  reach,  then  took  a  step  and  secured  two  pieces 
farther  away ;  after  having  secured  a  fifth  piece  she  dropped  it 
before  getting  it  to  her  mouth  and  it  rolled  away  about  10  cm. 
from  its  original  position  but  she  secured  it  immediately;  then 
she  secured  pieces  of  carrot  and  of  apple  which  had  fallen  in  the 
shadow;  finally  she  looked  outside  the  cage  and  secured  two 
remaining  pieces  which  had  rolled  outside  the  cage.  Two  small 
wads  of  cotton  were  dropped  in  the  cage;  for  a  time  she  dis- 
regarded these,  but  picked  up  similarly  sized  pieces  of  apple  and 
carrot,  but  finally  she  picked  up  one  piece  of  cotton  and  placed 
it  in  her  mouth.  A  piece  of  sugar  was  silently  placed  on  the  floor 
of  the  cage  about  70  cm.  away  from  the  animal ;  she  stopped  try- 
ing to  pick  up  the  small  particles  of  food  near  her,  made  three 
steps  and  accurately  grasped  the  sugar;  another  piece  was 
dropped  into  the  cage  and  it  rolled  close  to  the  body  of  the  animal ; 
she  peered  around  but  did  not  secure  it,  then  moved  away  about 
30  cm.,  turned  around,  immediately  reached  for  and  secured  it; 
a  third  piece  was  dropped  in  the  cage  in  the  shadow ;  for  about  a 
half  minute  this  was  unnoticed  but  then  she  made  five  steps  and 
with  an  accurate  arm  movement  secured  it.  Quick  movements 
of  the  experimenter's  hands  and  arms  in  any  direction  made  the 
animal  start  and  crouch  in  a  corner;  fingers  and  sticks  placed 
through  the  wire  netting  were  also  startling.  A  piece  of  raw 
potato  was  placed  in  and  stuck  by  its  moisture  to  the  bottom  of 
a  glass  crystallizing  dish,  5  cm.  diam.,  the  dish  was  then  placed 
in  the  cage  bottom  side  upwards ;  the  monkey  reached  for  the  dish. 


EXPERIMENTAL  RESULTS  67 

made  the  proper  adjustment,  picked  up  the  dish,  turned  it  in  the 
proper  position  and  tried  to  get  the  potato  by  putting  the  mouth 
in  the  dish ;  when  she  could  not  get  the  food  in  this  way,  she  put 
out  her  tongue,  dislodged  the  food,  secured  it  with  the  right  hand 
while  the  dish  was  held  with  the  left.  A  fly  on  the  cage  20  cm. 
away  and  to  the  right  was  caught  at  but  not  secured  although  the 
movement  was  accurate.  A  small  piece  of  apple  was  wrapped  in 
a  piece  of  paper  and  placed  75  cm.  away,  the  package  was  secured 
immediately  and  opened  in  the  usual  way  by  teeth  and  hands. 
Similarly  with  other  packages. 

The  animal  was  killed  with  chloroform  at  n  130  a.  m.  so  that 
the  brain  could  be  examined  before  there  were  any  marked  ex- 
tensions of  the  lesions  and  before  any  repair  could  be  brought 
about. 


37 


39 


FIGS.  36,  37,  38  and  39.  Monkey  3.  Lateral  and  mesial  aspects  of  the 
cerebral  hemispheres,  showing  the  amount  of  the  cortex  involved  by  the 
operation.  Slightly  reduced.  Traced  from  photographs. 

The  autopsy  was  performed  fifteen  minutes  after  death.  The 
wound  was  healthy  in  appearance.  The  brain  showed  a  slight 
hernia  beneath  the  two  skull  openings  and  weighed  102  grams. 
On  account  of  the  brief  time  between  the  operation  and  autopsy, 


68 


SHEPHERD   IVORY  FRANZ 


the  brain  was  examined  only  for  the  destruction  of  cells  and  the 
c-xtent  of  lesion. 

Figures  36  to  45  show  the  amount  of  the  destruction  of  the 
cortex.  An  examination  of  the  microscopical  sections  (figs.  40 
to  45)  shows  that  comparatively  large  amounts  of  the  fibers  were 
destroyed  as  well  as  the  cortex,  and  the  cautery  undoubtedly  pene- 
t  rated  the  white  substance  as  well  as  burning  the  cortex.  It  will 
be  seen  that  the  cortex  in  the  neighborhood  of  the  calcarine  fissure 
has  entirely  escaped,  and  remained  normal,  while  the  greatest 
amount  of  destruction  took  place  over  the  convexity  of  the  hemi- 
spheres, being  more  marked  over  the  superior  portion. 


FIGS.  40,  41,  42,  43,  44  and  45.  Monkey  3.  Microscopical  findings  after  the 
cauterization  of  the  cortex. 

The  report  of  Dr.  Lafora  on  this  case  is  as  follows :  ''Monkey 
3,  Nissl  method,  frontal  sections.  On  the  right  side  the  de- 
struction of  the  calcarine  type  of  cortex  was  fairly  complete  to- 
wards the  occipital  pole  except  along  the  calcarine  fissure.  The 
calcarine  fissure  is  affected  only  in  its  profundity  by  a  reactive 
process  which  arose  from  the  injury  to  the  external  part  of  the 
hemisphere.  On  the  left  side  the  lesions  are  a  trifle  more  exten- 


EXPERIMENTAL  RESULTS  69 

sive,  but  the  calcarine  fissure  is  affected  only  in  its  extreme  depth. 
The  external  part  of  the  lobe  is  almost  entirely  destroyed." 

From  the  accounts  of  the  histological  findings  and  of  the  clini- 
cal appearances  of  the  monkey  following  the  operation,  it  is  plain 
that  the  visual  defects  are  not  in  proportion  to  the  amount  of 
destruction  of  the  so-called  visual  cortex,  and  that  the  lack  of 
blindness  can  not  be  ascribed  to  the  failure  to  destroy  the  part 
of  the  brain  which  is  supposed  to  have  visual  functions.  This 
case  is  to  be  compared  with  that  of  monkey  5,  in  which  latter 
the  calcarine  fissure  was  destroyed  more  than  the  remainder  of 
the  visual  cortex,  and  the  clinical  accounts  of  each  of  these  mon- 
keys differ  to  an  extent  to  be  paralleled  by  the  microscopical 
findings. 

The  animal  retained  its  visual  function  to  a  very  great  degree 
and  the  disturbance  in  function  can  be  said  to  be  almost  exclusively 
a  dissociation  between  the  sensations  from  the  eyes  and  the 
movements  of  the  hand  (and  other  parts).  The  observations  do 
not  indicate  a  visual  defect  per  se. 

Monkey  4.  This  animal  had  been  trained  by  Dr.  Shepherd  in 
his  experiments,  and  about  eight  months  later  for  a  period  of 
about  nineteen  days  it  was  trained  to  discriminate  blue  (sweet) 
from  green  (bitter)  and  yellow  (bitter)  breads.  At  this  time 
the  habit  of  taking  the  blue  and  leaving  the  green  and  yellow 
was  firmly  established.  No  further  experiments  were  done  for 
about  seven  months  at  the  end  of  which  time  the  animal  appeared 
to  have  almost,  perfect  retention  of  the  habit  and  reacted  properly 
to  the  conditions  as  is  indicated  in  the  accompanying  account. 

July  30,  5  tests;  in  the  first  test  the  monkey  took  the  piece  of 
bine  bread  at  first  and  then  the  piece  of  green,  but  threw  the  latter 
away  without  eating  it;  the  fifth  test  on  this  day  was  made  with 
two  pieces  each  of  the  three  colors  arranged  in  an  irregular  order 
and  the  animal  took  only  the  blue  breads.  July  31.  3  tests;  in  all 
tests  the  animal  took  only  the  blue  bread;  but  did  not  pay  any 
attention  to  the  foods  after  the  third  test  and  the  series  could  not 
be  continued  on  that  day.  August  7,  5  tests;  in  all  these  tests, 
after  the  interval  of  seven  days,  the  animal  took  only  the  blue 
bread;  at  first  it  did  not  work  rapidly  but  looked  around  and 
paid  no  attention  to  the  breads  for  several  minutes  after  they 


70  SHEPHERD   IVORY  FRANZ 

were  placed  before  it;  twelve  pieces  each  of  blue,  yellow  and 
green  were  arranged  on  a  board  in  an  irregular  order  and  pre- 
sented to  the  animal  which,  after  intervals,  took  ten  of  the  blue 
pieces  and  disregarded  the  yellow  and  green.  August  16,  5  tests; 
in  all  the  tests  the  monkey  took  only  the  blue  bread;  in  an  addi- 
tional test  in  which  five  pieces  each  of  blue,  yellow  and  green 
were  presented  at  one  time  the  animal  took  only  the  blue;  it  is 
worthy  of  note  in  connection  with  the  discussion  of  color  vision 
that  in  the  last  experiment  the  yellow  bread  had  been  colored  by 
a  solution  of  lead  chromate  instead  of  the  usual  methyl  orange, 
with  which  it  had  been  previously  tested. 

Operation,  August  1 7,  2  130  p.  m.  On  the  right  side  an  at- 
tempt was  made  to  cut  away  the  occipital  pole  from  the  rest  of 
the  cerebrum  by  means  of  the  cataract  knife;  on  the  left  the 
mesial  aspect  was  cauterized  and  the  cautery  was  thrust  inwards 
and  forwards.  The  hemorrhage  was  considerable  on  the  right 
side,  but  it  was  checked  by  the  application  of  I  :  1000  suprarenal 
solution  and  by  hot  sponges.  The  animal  remained  lethargic  for 
some  time  after  the  operation,  but  at  4 130  p.  m.  it  was  found  sit- 
ting up  in  its  cage,  apparently  alert  and  bright.  He  appeared  to 
see  a  hand  threatening  him  no  matter  from  which  direction  the 
hand  was  approached.  At  7  p.  m.  I  found  the  animal  had  torn 
the  bandage  away ;  after  washing  the  head  thoroughly  with  bi- 
chloride, i  :  500,  I  replaced  the  gauze  dressing  and  bandages  and 
thoroughly  sewed  them  together.  An  hour  later  the  animal  was 
quiet  but  appeared  to  see  a  small  stick  thrust  at  him  from  right, 
left,  above  and  below  for  he  moved  away  from  the  stimulus. 

About  twenty  hours  after  the  operation,  the  animal  was  found 
quietly  sitting  in  its  cage.  A  piece  of  bread  placed  on  the  floor 
of  the  cage  was  not  noticed  for  about  three  minutes,  but  at  the 
end  of  that  time  the  animal  moved  toward  it,  made  an  accurate 
movement,  picked  it  up  and  ate  it.  A  dish  of  water  was  placed 
in  the  cage,  and  he  immediately  moved  near  the  dish,  put  his  head 
down  and  drank.  Four  small  pieces  of  food,  one  each  of  bread, 
cake,  boiled  potato,  and  cantaloupe,  of  about  equal  sizes  were 
placed  on  the  floor  of  the  cage ;  the  animal  selected  the  cantaloupe 
first,  then  took  the  cake  and  the  potato  and  left  the  bread.  In 
four  similar  tests,  the  same  result  was  obtained,  but  it  was  noticed 


EXPERIMENTAL  RESULTS  l\ 

that  at  times  the  monkey  took  the  bread  but  threw  it  away  without 
attempting  to  eat  it.  The  movements  of  grasping  were  usually 
made  with  an  error  of  about  3  cm.  In  these  experiments  the 
animal  did  not  always  take  the  food  in  its  hand  from  the  normal 
sitting  posture,  but  usually  lowered  its  head  toward  the  food 
before  reaching  for  it.  It  was  concluded  that  this  indicated  an 
impairment  of  vision,  and  the  inaccuracies  in  hand  adjustments 
for  the  grasping  of  food  were  taken  as  confirmations  of  this 
conclusion ;  the  impairment  seemed  to  be  not  a  blindness,  but  only 
a  dimness  of  vision. 

Twenty-six  hours  after  the  operation.  Two  sticks  were  sim- 
ultaneously introduced  into  the  cage,  one  to  the  right  and  the 
other  to  the  left  of  the  animal;  that  on  the  right  attracted  the 
attention  of  the  animal  and  was  seized,  that  on  the  left  was  not 
seized  even  when  it  was  advanced  to  within  a  few  inches  of  the 
head  of  the  animal.  One  of  the  sticks  was  held  near  the  floor, 
the  other  above  the  level  of  the  eyes;  the  animal  reached  for 
the  upper  stick  and  disregarded  the  lower  one  until  it  had  been 
moved  so  as  to  touch  the  body.  The  movements  of  grasping  the 
stick  on  the  right  were  as  accurate  as  before  the  operation,  those 
of  grasping  the  stick  above  the  level  of  the  eyes  and  those  near 
the  floor  were  very  inaccurate.  The  colored  breads,  when  pre- 
sented to  him,  were  disregarded  and  the  test  of  this  visual  func- 
tion was  unsuccessful.  The  animal  was  able  to  see  food  and 
other  objects  on  the  floor  of  the  cage  but  it  was  not  detern-ined 
in  what  manner  this  was  accomplished.  From  the  peculiar  move- 
ments of  the  head,  the  lowering  and  the  turning,  it  appeared  to 
be  necessary  for  the  animal  to  get  the  visual  image  on  the  lower 
retinal  segment,  for,  although  an  object  lying  on  the  floor  was 
approached,  it  was  not  taken  until  the  head  had  been  lowered  a*.id 
the  eyes  turned  downwards.  The  direction  of  the  errors  (right 
and  left)  in  taking  the  food  were  not  recorded. 

Two  days  after  the  operation,  the  animal  went  into  the  small 
observation  cage  as  soon  as  the  door  was  opened.  At  that  tune 
the  animal  was  more  lively  than  it  had  been  and  its  actions  were 
apparently  normal.  It  picked  up  food  lying  upon  the  floor  of 
the  cage.  When  the  hand  was  held  above  the  cage  the  animal 
showed  signs  of  fright,  shrinking  into  a  corner,  etc.  A  piece  of 


72  SHEPHERD   IVORY  FRANZ 

pear  held  above  the  level  of  the  eyes  was  seized  quite  accurately. 
Two  pieces  of  pear  were  held  simultaneously  on  a  level  with  the 
eyes,  one  to  the  right,  the  other  to  the  left,  each  about  10  cm.  in 
front  of  and  to  the  side  of  the  median  line;  the  animal  always 
took  the  piece  on  the  left  first,  sometimes  with  the  right  hand, 
sometimes  with  the  left.  A  rod  and  a  piece  of  pear  were  held 
simultaneously  in  the  upper  part  of  the  field;  when  the  rod  was 
on  the  left  it  was  seized  and  the  pear  was  disregarded ;  when  the 
pear  was  on  the  left  it  was  seized  and  the  rod  disregarded.  A  rod 
held  about  15  cm.  below  the  level  of  the  eyes  was  disregarded  until 
the  head  was  moved  or  until  the  rod  touched  the  body  or  the 
hair.  The  animal  peered  through  the  opening  at  the  back  of 
the  cage  with  all  the  appearance  of  the  investigation  of  a  normal 
animal. 

On  the  same  day,  four  hours  later,  the  animal  was  tested  and 
examined  by  Dr.  Lafora,  who  reported  as  follows:  "Pupils  react 
well  to  light.  Held  yellow  and  blue  breads  before  the  animal 
twice,  and  each  time  the  animal  took  the  yellow  bread  first  and 
the  blue  afterwards.  A  piece  of  melon  and  blue  bread,  the  latter 
nearer  the  animal  were  presented  simultaneously,  and  the  monkey 
reached  beyond  the  blue  bread  and  took  the  melon.  Two  pieces 
of  melon  (one  held  in  the  visual  axis  and  the  other  to  the  right, 
left,  superior  or  inferior)  were  presented  simultaneously,  and 
each  time  the  animal  took  both  pieces,  apparently  seeing  with  all 
parts  of  the  visual  field.  For  testing  the  ability  to  see  in  the  lower 
part  of  the  visual  field  a  board  was  placed  near  the  bottom  of 
the  cage  so  that  food  in  the  hand  could  be  kept  out  of  sight  until 
it  was  time  to  show  it ;  in  the  right  hand  a  piece  of  food  was  held 
in  front  of  the  animal  in  order  to  attract  the  attention,  but  just 
beyond  the  reach  so  that  the  animal  would  need  to  exert  himself 
in  his  efforts  to  obtain  the  food,  and  a  second  piece  was  held  in 
the  other  hand  behind  the  board ;  the  attention  of  the  monkey  was 
gained  by  the  exhibition  of  the  piece  of  food  in  the  right  hand, 
but  when  the  second  piece  was  exposed,  the  animal  reached  for 
the  latter.  Two  tests  were  made  with  pieces  of  green  and  white 
breads  after  having  performed  many  tests  with  melon  and  white 
bread ;  in  the  later  tests  the  animal  always  reached  for  the  green 
bread;  in  tests  with  green  and  blue  breads  in  which  the  green 


EXPERIMENTAL  RESULTS  73 

bread  was  held  nearer  the  animal  than  the  blue,  the  monkey  always 
reached  beyond  the  green  bread  and  selected  the  blue  bread. 
When,  however,  the  blue  bread  was  held  in  the  inferior  and  the 
green  in  the  superior  part  of  the  field  the  green  was  always  taken. 
When  a  piece  of  melon  and  a  piece  of  green  bread  were  shown 
simultaneously  the  animal  always  selected  the  green  melon.  Under 
the  following  conditions  the  animal  always  selected  the  vegetable 
or  fruit  instead  of  the  bread;  blue  bread  and  tomato;  blue  bread 
and  melon;  green  bread  and  tomato;  green  bread  and  melon; 
even  when  the  bread  was  nearer  or  farther  from  the  animal,  to 
the  right  or  to  the  left,  and  when  one  or  more  pieces  were  pre- 
sented simultaneously.  Repeated  tests  to  determine  whether  or 
not  both  right  and  left  visual  fields  were  normal  showed  that  the 
animal  made  grasping  movements  for  food  regardless  of  the  part 
of  the  field  in  which  the  food  was  presented,  but  that  the  move- 
ments for  food  on  the  right  were  not  as  quick  as  those  on  the 
left.  When  pieces  of  melon  or  tomato  were  held  in  the  hand 
close  to  the  cage  the  animal  always  took  them,  but  did  not  take 
the  green,  red  or  yellow  breads." 

Four  days  after  the  operation.  When  a  plum  was  thrown  into 
the  cage  the  animal  moved  toward  it  and  tried  to  pick  it  up  but 
failed  several  times  to  locate  the  fruit.  At  first  it  grasped  another 
piece  of  food  which  it  then  smelled  and  rejected,  and  continued 
to  seek  the  plum  until  it  was  found. 

Five  days  after  the  operation.  A  paralysis  of  both  hands  was 
found,  the  fingers  were  shut  into  a  fist  and  there  was  a  wrist 
drop.  The  movements  of  the  arm  appeared  to  be  normal,  and  it 
was  found  that  when  the  arms  were  extended  the  fingers  were 
voluntarily  moveable  to  a  slight  extent.  When  a  pear  was  rolled 
on  the  floor  of  the  cage  the  animal  moved  toward  it  and  attempted 
to  get  it  in  his  hands  but  on  account  of  the  flexion  of  the  fingers 
could  not  do  this ;  the  pear  was  then  eaten  by  the  animal  moving 
its  head  close  to  the  pear.  The  pear  and  other  pieces  of  food 
were  held  to  a  slight  extent  by  the  thumbs  of  both  hands,  which 
appeared  to  be  more  moveable  than  the  fingers. 

On  the  following  day  (six  days  after  the  operation),  the  paral- 
ysis of  the  hands  disappeared;  the  movements  of  grasping  and 
of  holding  were  normal  in  character,  and,  judging  from  the  force 


74  SHEPHERD   IVORY  FRANZ 

with  which  it  held  a  rod  inserted  into  a  cage,  of  good  force.  The 
monkey  did  not  eat  any  bread  presented  to  it,  and  the  colored 
breads  were  disregarded;  on  this  account  a  test  of  the  color  dis- 
crimination could  not  be  made.  All  fruits  and  vegetables  were 
rapidly  and  unerringly  selected  from  the  food  presented  to  him  so 
that  it  was  evident  the  animal  had  considerable  discrimination 
ability.  The  animal  was  not  fed  at  this  time  and  in  the  afternoon 
tests  with  the  colored  breads  were  made.  In  two  tests  the  mon- 
key selected  the  blue  bread  and  disregarded  the  yellow  and  green, 
but  on  the  third  test  the  animal  picked  up  at  one  time  both  the 
blue  and  the  green,  disregarding  the  yellow. 

Two  days  later  (eight  days  after  operation).  Tests  with  the 
colored  breads ;  in  three  tests  took  blue  bread  and  in  the  third  took 
yellow  after  having  eaten  the  blue,  but  did  not  eat  the  yellow ;  in  a 
fourth  test  in  which  two  pieces  each  of  yellow,  red  and  blue 
breads  were  presented  simultaneously  in  irregular  order,  the 
monkey  took  the  blue  pieces,  brushed  the  red  pieces  off  the  plate 
and  disregarded  the  yellow  bread.  Tests  with  small  pieces  of 
bread,  cooked  potato,  raw  apple,  cooked  green  beans,  and  raw 
tomato  resulted  in  the  selection  of  the  vegetables  and  the  dis- 
regarding of  the  bread. 

Ten  days  after  operation.  The  animal  was  found  in  a  convul- 
sion with  twitchings  of  arms,  head,  eyelids,  etc.  The  fingers  were 
flexed  as  they  had  been  five  days  previously,  and  there  was  in- 
ability to  grasp  food ;  the  condition  passed  away  by  the  following 
day,  and  the  animal  caught  with  accuracy  grapes  rolled  toward 
him  on  either  side  and  placed  them  in  his  mouth.  Other  foods 
were  selected  from  bread,  their  positions  were  accurately  judged 
(as  evidenced  in  the  accuracy  of  the  movements)  and  they  were 
eafen. 

Five  days  later  (fifteen  days  after  the  operation).  Color  tests; 
took  only  blue  bread.  The  animal  was  killed  on  this  day  in  order 
that  examinations  of  the  brain  might  be  made  by  the  methods  of 
Marchi. 

Figures  46  to  57  show  the  results  of  the  post  mortem  examina- 
tions. In  figs.  46  to  49  are  shown  the  results  of  the  lesions.  The 
extent  of  the  cortex  destroyed  by  the  cautery  was  accurately 
determinable  but  on  account  of  the  character  of  the  operation  on 


EXPERIMENTAL  RESULTS 


75 


47 


51 


SOI 


49 


FIGS.  46,  47,  48  and  49.  Monkey  4.  Lateral  and  mesial  aspects  of  the 
cerebral  hemispheres,  showing  the  extents  of  the  lesion  of  the  cortex  on 
the  left  side,  and  the  approximate  course  of  the  knife  cut  on  the  right. 
Slightly  reduced.  Traced  from  photographs. 


JQlC*  _  _ 
f  153.  53 

ol 


FIGS.  50,  51  and  52.  Monkey  4.  Frontal  sections  of  the  left  hemisphere  in 
the  neighborhood  of  the  cauterization,  showing  the  amount  of  destruction. 
Slightly  enlarged.  Drawn  with  Edinger  projection  apparatus. 


76  SHEPHERD   IVORY  FRANZ 

the  right  side  it  was  not  possible  to  determine  the  amount  of  the 
visual  area  involved  by  the  operation.  The  approximate  location 
of  the  knife  cut  on  the  right  side  is  shown  in  the  figure.  The 
results  shown  in  figs.  50,  51  and  52  are  due  to  the  cauterization 
of  the  cortex,  and  have  been  investigated  by  the  Nissl  method.  In 
parts  it  will  be  noted  that  the  depth  of  the  cortical  destruction 


FIGS.  53.  Monkey  4.  Vertical  section  through  the  left  hemisphere,  anterior 
to  the  cauterized  area.  Few  fat  drops  are  indicated  in  the  diagram  by 
crosses.  Slightly  enlarged.  Edinger  drawing  apparatus. 

has  not  been  great,  a  matter  which  has  been  considered  in  an 
earlier  portion  of  this  article.  The  section  of  the  left  hemisphere 
anterior  to  the  parts  examined  by  the  Nissl  method  was  examined 
for  fiber  disintegration,  or  degeneration,  and  this  showed,  figure 
53,  a  rather  diffuse  process,  but  with  no  marked  evidences  of 
degeneration.  The  examination  of  the  right  hemisphere  by  the 
Marchi  method  was  unsatisfactory,  for  the  only  effects  of  the 
lesion  were  those  in  the  immediate  neighborhood  of  the  cut. 

Regarding  these  preparations  Dr.  Lafora  has  written:  "Mon- 
key 4.  Cauterization  of  the  left  hemisphere,  cutting  of  the  white 
matter  of  the  right  hemisphere.  Frontal  sections.  Nissl  method 
on  the  left,  and  Marchi  method  on  the  right.  On  the  left  the 
calcarine  fissure  has  almost  entirely  escaped  destruction.  The 
outside  of  the  brain  (the  calcarine  type  of  cortex)  is  affected  in 
the  external  layers  up  to  the  granularis  interna.  (On  account  of 


EXPERIMENTAL  RESULTS 


77 


the  time  of  death  so  soon  after  the  operation  the  cortex  showed 
only  the  primary  effects  of  the  operation  and  not  the  secondary 
ones.)  A  large  hemorrhage  extends  over  the  calcarine  type  of 
cortex  on  the  lateral  aspect  of  the  hemispheres  and  extends  into 
the  white  substance.  Sections  of  the  brain  anterior  to  the  cauter- 
ized area  were  examined  by  the  Marchi  method,  and  these  showed 
some  fat  drops  as  are  illustrated  in  the  figures.  The  right  side 
was  placed  in  toto  by  mistake  into  the  Marchi  fluid  which  pro- 


FIGS.  54,  55,  56  and  57.  Monkey  4.  Frontal  sections  of  right  hemisphere, 
showing  destruction  in  the  neighborhood  of  the  knife  cuts.  For  fuller 
description,  see  text.  Slightly  enlarged.  Edinger  drawing  apparatus. 

cedure  did  not  permit  a  proper  impregnation,  consequently  tht 
appearances  found  in  the  sections  are  only  those  near  the  surface. 
Here  are  found  many  fat  drops  around  the  hemorrhagic  areas, 
which  were  produced  by  the  cutting." 


;8  SHEPHERD   IVORY  FRANZ 

Clinically,  it  appeared  at  first  as  if  this  animal  had  a  visual 
defect  but  later  observation  failed  to  indicate  this,  and  the  con- 
clusion is  forced  upon  us  that  if  there  was  a  defect  during  the 
first  few  days  it  was  minor  in  character,  and  not  of  sufficient 
amount  to  be  called  amblyopia,  hemianopsia,  or  anything  more 
than  what  Loeb  has  called  a  "reduction  in  irritability." 

Monkey  5.  In  the  preliminary  experiments  this  animal  had 
been  trained  to  take  red  and  blue  breads  and  to  disregard  the 
yellow  and  green.  These  early  experiments  were  made  on  eight- 
een days  over  a  period  of  sixty-one  days,  the  habit  being  estab- 
lished after  five  days'  experimentation.  No  further  experiments 
were  made  for  eight  months. 

August  19,  4  tests;  took  red,  blue  and  green  the  first  test;  red 
and  blue  the  second  test,  and  only  blue  the  third  and  fourth  tests. 
August  20,  5  tests  were  made  with  only  red,  yellow  and  blue,  and 
in  all  the  tests  the  animal  disregarded  the  yellow.  August  23, 
after  an  interval  of  three  days,  10  tests  were  made  with  blue,  yel- 
low and  green.  In  the  first  test  the  animal  took  the  yellow  as  well 
as  the  blue,  but  in  the  other  nine  tests  took  only  the  blue.  August 
25,  10  tests;  took  only  the  blue  and  disregarded  the  yellow  and 
green.  On  the  last  two  days  one  test  each  was  made  in  which 
two  or  more  pieces  of  each  of  the  three  kinds  of  bread  were 
presented  simultaneously,  and  in  these  tests  the  animal  selected 
the  blues  from  the  other  colored  breads. 

August  26.  Operation.  Both  occipitals  were  cauterized,  the 
cautery  being  inserted  into  the  brain  substance  as  well  as  being 
passed  over  the  cortex. 

Three  hours  after  the  operation  the  animal  appeared  to  be 
fairly  normal.  He  picked  up  pieces  of  apple  placed  on  the  floor 
of  the  cage,  the  color  of  which  was  quite  similar  to  that  of  the 
food.  The  movements  were  accurate  when  the  food  was  placed 
within  30  cm.  of  the  animal,  and  in  addition  the  animal  made 
accurate  movements  to  secure  food  held  at  the  top  of  the  cage. 

Four  and  a  half  hours  after  the  operation,  the  animal  was  ob- 
served by  me  in  conjunction  with  Dr.  I.  W.  Blackburn.  At  this 
time  the  following  notes  were  made :  The  pupils  reacted  to  light 
in  a  normal  manner,  and  the  general  appearance  of  the  animal  was 
normal.  He  peered  around  the  cage  and  through  the  opening  in 


EXPERIMENTAL  RESULTS  79 

the  back,  and  examined  all  things  placed  in  his  way.  In  his  usual 
manner  to  strangers,  he  threatened  Dr.  Blackburn,  but  afterwards 
remained  huddled  in  a  corner,  but  moved  whenever  the  hand  was 
inserted  into  the  cage  or  when  food  was  presented.  Grapes  rolled 
toward  the  animal  were  immediately  and  accurately  seized ;  grapes 
held  in  the  hand  30  cm.  distant  were  reached  for  but  not  accurate- 
ly grasped,  for  at  times  he  took  hold  of  the  experimenter's  finger. 
A  grape  rolled  to  the  other  end  of  the  cage  (75  cm.  distance  from 
the  animal)  was  disregarded  for  ten  or  fifteen  seconds,  although 
the  animal  was  hungry  and  ate  anything  placed  within  its  reach. 
Grapes  and  pieces  of  apple  placed  near  enough  to  be  reached  were 
easily  grasped,  but  at  times  with  slight  incoordination  amounting 
to  about  4  cm.  The  grasping  movements  were  sometimes  to  one 
side,  at  other  times  to  the  other,  and  often  nearer  the  animal  than 
they  should  have  been.  A  mirror  placed  in  the  cage  attracted  the 
attention,  the  animal  moved  toward  it,  peered  into  it  and 
examined  the  front  and  looked  behind  it  repeatedly.  He  took  a 
piece  of  red  colored  blotting  paper  and  inserted  it  into  the  mouth, 
but  then  rejected  it.  A  small  piece  of  bread  about  3  mm.  in  dia- 
meter was  picked  up  from  the  floor,  but  as  he  continued  to  fumble 
for  food  and  at  times  picked  up  grape  skins  which  he  had  previ- 
ously rejected  it  was  impossible  to  decide  whether  the  small  piece 
of  bread  had  been  seen  or  had  been  hit  by  the  hand  as  the  animal 
moved  the  hand  over  the  floor.  The  monkey  repeatedly  took  the 
grape  skins  which  it  had  previously  rejected,  placed  them  in  the 
mouth  and  immediately  spat  them  out  again.  A  pair  of  eyeglasses 
were  held  so  that  four  images  of  the  electric  lights  were  thrown 
on  the  floor  of  the  cage;  these  attracted  the  attention  of  the 
animal  and  he  moved  his  head  and  eyes  in  accordance  with  the 
movements  of  the  images. 

Four  days  after  the  operation.  It  was  noted  that  when  food 
held  on  wires  was  presented  to  the  animal,  the  food  held  in  the 
upper  left  visual  field  was  always  seized  immediately,  but  that 
the  food  held  in  other  parts  of  the  field  was  sometimes  seized  and 
sometimes  not  seized.  On  this  day  an  attempt  was  made  to  test 
the  memory  for  colors  but  the  animal  would  not  touch  the  breads 
and  the  test  could  not  be  made. 

On  the  following  day,  five  days  after  the  operation,  the  tests 


So  SHEPHERD   IVORY   FRANZ 

with  colored  breads  on  the  glass  plate  were  also  unsuccessful,  and 
the  breads  were  therefore  presented  in  pairs  on  wires,  viz.,  blue 
and  yellow,  and  blue  and  green.  In  ten  tests  with  the  yellow-blue 
pair  the  monkey  took  the  yellow  once,  the  blue  four  times,  and 
both  pieces  five  times.  The  latter  result  was  obtained  after  the 
other  five.  With  the  green-blue  test,  the  monkey  took  the  blue 
five  times,  and  did  not  take  the  green.  On  this  day  a  lump  of 
sugar  was  placed  at  the  bottom  of  the  cage  but  it  remained  un- 
noticed although  before  the  operation  the  animal  was  very  fond 
of  sugar.  Other  pieces  of  food  on  the  floor  of  the  cage  were 
also  disregarded,  although  when  food  was  placed  close  to  the  nose 
it  was  seized  and  eaten  with  eagerness.  A  broom  and  a  stick,  of 
which  the  animal  was  normally  afraid,  were  introduced  into 
the  cage  without  producing  any  reaction  on  the  part  of  the 
animal. 

Six  days  after  the  operation  the  tests  with  colored  breads  were 
more  successful.  Five  tests  were  made  with  the  following  re- 
sults :  In  the  first  test  the  animal  reached  in  the  direction  of  the 
blue,  but  slowly  drew  its  hand  backwards  and  then  put  its  head 
down  to  the  food  plate  and  took  the  blue  in  the  mouth.  In  the 
second  test,  the  animal  fumbled  about  the  plate,  finally  hit  the 
yellow  bread,  which  it  placed  in  its  mouth  but  immediately  spat 
out.  In  the  third  test  he  grabbed  for  the  bread,  caught  the  green 
piece,  which  was  tasted  and  thrown  away,  and  then  he  took 
the  blue  which  he  ate.  In  the  fourth  test,  he  took  the  blue  bread 
immediately,  ate  it  and  disregarded  the  other  two  pieces.  In 
the  fifth  test  he  took  the  blue,  but  only  tasted  it ;  the  other  pieces 
were  not  touched.  Following  these  experiments  he  was  placed  in 
the  cage  with  another  animal.  As  soon  as  he  got  into  the  other 
cage  he  walked  half  way  across  the  cage  and  picked  up  a  piece  of 
food  lying  on  the  floor,  and  then  stood  up  and  reached  for  a 
piece  of  apple  on  the  wire  netting  at  the  top.  Small  pieces  of 
apple  were  then  placed  at  the  top  of  the  cage  to  the  right  or  left 
of  the  animal,  and  in  every  case  he  accurately  reached  for  the 
food.  In  one  test  in  which  two  pieces  were  placed  about  10  cm. 
apart,  he  reached  for  one  piece,  but  in  taking  hold  of  the  netting 
the  apple  dropped  to  the  floor  of  the  cage  whereupon  he  immedi- 
ately changed  the  direction  of  the  movement  and  secured  the  sec- 


EXPERIMENTAL  RESULTS 


81 


ond  piece.  After  having  secured  the  second  piece  he  accurately 
reached  for  and  secured  the  first  piece  which  had  fallen  to  the 
floor. 

During  the  next  three  days  the  inaccuracies  in  reaching  for 
food  increased,  until  the  animal  was  able  to  get  food  only  by 
fumbling  around  on  the  bottom  of  the  cage.  Eventually  his 
movements  became  like  those  of  a  blind  person.  Ten  days  after 
the  operation  it  was  noted  that  the  animal  had  all  the  appearance 
of  being  blind.  He  paid  no  attention  to  the  movements  of  the 
experimenter's  hand  and  arm  or  to  a  small  flag.  Food  held  at 
a  distance  of  30  cm.  was  unattended  to  except  when  held  in  the 
upper  left  part  of  the  visual  field.  He  reached  for  food  when 
it  was  placed  on  the  floor  of  the  cage  but  the  movements  were 
inaccurate  and  it  appeared  that  the  animal  did  not  appreciate 


6S 


FIGS.  58,  59,  60  and  61.  Monkey  5.  Lateral  and  mesial  aspects  of  the 
cerebral  hemispheres,  showing  the  extent  of  the  lesions  produced  at  the 
operation:  Slightly  reduced.  Traced  from  photographs. 


what  he  was  reaching  for.    Once  a  small  bright  red  tomato  about 
2  cm.  in  diameter  was  exhibited  in  the  upper  left  part  of  the  field ; 


82  SHEPHERD   IVORY  FRANZ 

the  monkey  reached  for  it  in  a  fumbling  manner  and  knocked  it 
down  so  that  it  rolled  to  the  left  and  behind  him.  He  sought  for 
the  food  through  the  bars  of  the  cage,  although  none  was  visible, 
and  groped  hither  and  thither.  When  the  tomato  was  shown  a 
second  time  in  the  upper  left  field,  he  reached  for  it,  making  an 
initial  error  of  about  10  cm.,  but  finally  managed  to  secure  it. 
Black  and  white  grapes  rolled  on  the  floor  of  the  cage  were  not 
taken  although  the  animal  seemed  eager  for  food.  Grapes  held 
near  his  nose  were  taken  hold  of  accurately.  In  the  tests  made 
on  this  day  it  should  be  mentioned  that  there  was  an  intention 
tremor  and  part  of,  if  not  all,  the  inaccuracy  of  movement,  may 
have  been  due  to  this  motor  derangement. 

Eleven  days  after  the  operation  the  animal  was  tested,  and 
found  to  be  in  almost  the  same  condition  as  that  noted  in  the 
preceding  paragraph,  except  that  there  was  less  ability  to  grasp 
things  presented  to  him.  He  was  killed  on  this  day.  At  the 


FIGS.  62,  63,  64,  65,  66  and  67.  Monkey  5.  Frontal  sections  of  the  cerebral 
hemispheres,  showing  the  parts  affected  by  the  operation.  In  64  no  lesion 
was  found.  Edinger  drawing  apparatus.  Slightly  enlarged. 

autopsy  the  brain  was  found  bulging  above  the  level  of  the  bone, 
the  hernia  on  the  right  side  being  more  marked  than  that  on  the 
left.  There  were  adhesions  between  the  brain  and  dura  and 
scalp.  The  brain  weighed  92  grams. 


EXPER1  Ml- \T.\L  RESULTS  83 

The  results  of  the  post  mortem  examinations  in  this  animal 
showed  much  more  extensive  lesions  than  in  any  other  animal 
upon  which  I  operated.  The  visual  defect  was  noticeable  only 
after  four  or  five  days  (although  there  was  some  incoordination 
from  the  first)  and  in  this  case  it  is  apparent  that  the  end  result, 
the  apparent  blindness,  must  have  been  due  to  the  extension  of  the 
effects  of  the  primary  lesion.  Only  the  anterior  part  of  the  cal 
carine  fissure  on  the  right  side  was  preserved  (see  figs.  59  and  64) 
and  the  preservation  of  this,  with  the  apparent  lack  of  foveal 
vision  is  against  the  hypothesis  of  Henschen. 

The  results  of  the  histological  examination  by  Dr.  Lafora  arc 
as  follows:  "Monkey  5.  Cauterization  of  the  cortex.  Frontal 
sections,  Nissl  method.  On  the  right  side,  with  the  exception  of 
the  most  anterior  portion  of  the  calcarine  fissure,  which  is  a  very 
small  area,  all  of  the  calcarine  type  of  cortex  has  been  destroyed, 
even  the  external  part  of  the  occipital  pole,  and  large  parts  of 
the  white  substance  in  the  neighborhood  of  the  calcarine  fissure. 
On  the  left  side  the  lesion  was  apparently  selective,  for  the  effe:t 
is  localized  along  the  calcarine  fissure  throughout  its  entire  extent, 
and  into  its  depth.  The  occipital  pole  has  only  the  outside  part 
of  the  cortex  destroyed." 

Monkey  6.  This  animal  was  trained  to  discriminate  red  and 
green  breads.  The  training  results  were  as  follows : 

August  22,  5  tests;  in  all  tests  the  animal  took  both  kinds  of 
bread.  August  24,  10  tests;  after  the  first  four  tests  the  animal 
did  not  eat  the  green,  although  on  the  sixth  test  she  picked  it 
up  but  discarded  it  without  smelling  or  tasting.  August  26,  5 
tests;  in  all  of  which  the  red  was  taken  and  the  green  was  noi 
taken.  August  27  and  28,  5  tests  each  day;  in  all  the  green  was 
disregarded  and  the  red  taken.  August  31,  5  tests;  took  only  red 
although  in  the  last  test  on  this  .day  four  pieces  of  red  and  six 
of  green  were  presented  simultaneously.  September  I,  5  tests: 
in  all  of  which  the  red  was  taken  and  no  green.  On  this  day  the 
operation  was  performed. 

Operation,  September  I.     After  the  trephine  buttons  were  re 
moved  the  openings  of  the  skull  were  enlarged  by  means  of  bone 
forceps  so  that  all  of  the  lateral  parts  of  the  occipital  lobes  were 
exposed.     At  the  time  of  the  operation  the  hemispheres  were 


84  SHEPHERD   IVORY  FRANZ 

separated  by  a  glass  spatula  and  the  internal  aspects  of  both  hemi- 
spheres were  cauterized  as  well  as  possible.  The  injury  in  this 
animal  was  apparently  more  extensive  than  in  animals  3,  4,  and 
5.  A  hemorrhage  from  one  of  the  large  occipital  arteries  was 
checked  by  an  application  of  suprarenal,  I  :iooo. 

A  half  hour  after  the  operation  the  animal  was  found  sitting 
in  its  cage,  apparently  looking  at  everything  passing,  for  she  fol- 
lowed me  with  her  head  and  eyes  when  moving  around  the  room. 

Two  hours  after  the  operation,  she  was  found  peering  through 
the  opening  at  the  back  of  the  cage,  and  when  I  quietly  moved 
toward  this  part  she  retreated  to  the  other  side  of  the  cage.  When 
I  was  seated  in  front  of  the  cage  and  made  movements  with  my 
hands  and  arms,  she  followed  with  her  eyes  all  the  movements 
in  a  perfectly  normal  manner.  The  reflexes  of  the  pupils  were 
normal.  Four  pieces  of  white  bread  were  put  into  the  cage,  the 
animal  appeared  to  look  at  these,  and  she  touched  some  and 
carried  one  to  her  mouth,  but  did  not  eat  it.  A  grape  rolled  into 
the  cage  among  the  pieces  of  bread  was  instantly  seized  and 
placed  in  the  mouth.  Three  grapes  were  placed  among  the  bread 
and  all  were  selected  and  the  bread  disregarded;  in  these  tests  it 
was  noted  that  the  error  of  movement  was  from  one  to  three  cm. 
Pieces  of  muskmelon  were  selected  unerringly  from  the  bread  of 
the  same  sizes.  Only  two  pieces  of  pear  were  taken  although 
six  were  placed  in  the  cage.  When  pieces  of  melon,  bread  and 
pear  were  presented  the  monkey  took  the  pieces  of  melon  and  left 
the  bread  and  pear,  and  when  grapes,  melon,  pear  and  bread  were 
presented  she  took  only  the  grapes. 

Five  hours  after  the  operation  she  was  observed  by  Dr.  Lafora, 
who  made  the  following  observations :  "Color  vision  was  tested 
by  the  ability  of  the  animal  to  discriminate  foods  of  different 
colors ;  red  bread  from  a  red  grape,  melon  from  green  bread,  and 
combinations  of  different  kinds  of  food.  In  these  experiments 
the  monkey  took  the  fruit  in  preference  to  the  bread,  but  she  did 
not  appear  to  be  hungry  and  after  about  ten  minutes  would  not 
attempt  to  secure  food.  Tests  of  peripheral  vision  by  means  of 
food  placed  at  the  ends  of  wires  showed  that  when  the  food  was 
in  any  part  of  the  visual  field  it  attracted  the  attention  of  the 
animal  and  there  were  no  results  that  could  be  taken  to  indicate  a 


EXPERIMENTAL  RESULTS  85 

contraction  of  the  visual  field,  nor  any  difference  in  sensation 
ability." 

One  day  after  the  operation,  when  sitting  quietly  in  front  of 
the  cage  observing  the  actions  of  the  animal,  there  being  no  food 
in  the  cage,  I  saw  her  make  a  quick  movement  in  the  air  thereby 
catching  a  fly  on  the  wing.  At  this  time,  the  monkey  did  not 
work  with  colored  breads,  entirely  disregarding  them  as  they 
were  presented  on  the  glass  plate.  Throughout  the  period  of 
observation  on  this  day,  the  animal  kept  picking  at  the  edges  of 
the  bandage  and  when  she  had  managed  to  get  a  small  piece  of 
cotton  she  would  hold  it  about  10  cm.  in  front  of  her  eyes,  as  if 
carefully  examining  it ;  at  times  she  placed  the  cotton  in  the 
mouth  and  eventually  threw  it  away. 

During  the  next  five  days  there  were  no  new  observations 
worthy  of  note,  the  animal  appearing  to  be  in  much  the  same 
condition  as  was  noted  the  day  following  the  operation.  On  the 
sixth  day  after  the  operation  it  was  first  noted  that  the  animal  did 
not  appear  to  see  objects  placed  on  the  floor  of  the  cage  for  she 
left  fruit  and  other  kinds  of  food  although  she  appeared  to  be 
hungry  and  took  all  things  presented  to  her  in  the  hand  or  on 
wires.  On  this  day  the  visual  defect  was  like  that  of  many  of 
the  animals,  indicated  by  an  inaccuracy  in  movements  in  grasping 
the  particles  of  food,  for  the  errors  in  movement  amounted  to 
from  one  to  four  cm.  On  this  day,  however,  four  tests  with  col- 
ored breads  were  made,  and  in  these  tests  she  picked  up  the  red 
bread  and  disregarded  the  green  three  times ;  and  in  the  fourth 
trial  she  moved  in  the  direction  of  the  red  but  managed  to  pick 
tip  the  green  which  was  only  two  cm.  away  from  the  red. 

Two  days  later,  eight  days  after  the  operation,  three  grapes 
were  dropped  into  the  cage ;  they  rolled  into  positions  forming  an 
irregular  triangle  with  the  apex  about  50  cm.  from  the  eyes  of 
the  animal.  The  monkey  made  repeated  efforts  to  obtain  the 
grapes  but  at  first  got  its  hand  15  cm.  too  close  to  its  body  and 
then  fumbled  around  until  she  by  chance  hit  one  of  the  grapes: 
this  grape  rolled  closer  to  the  animal  but  the  monkey  continued 
to  feel  around  in  the  spot  at  which  the  grape  had  been  felt  and 
at  this  time  she  did  not  manage  to  get  this  grape  or  the  other 
two  which  were  presented.  Afterwards  with  considerable  fum- 


86  SHEPHERD   IVORY  FRANZ 

bling  she  secured  the  two  grapes  the  positions  of  which  had  not 
been  disturbed  and  finally  the  one  which  had  been  moved  by  her 
fumbling,  and  which,  as  has  been  said,  rolled  closer  to  her  body. 
A  second  set  of  observations  were  made  on  this  day  with  some- 
what similar  results.  The  defect  of  vision  appeared  to  me  to  be 
general  and  not  of  any  particular  retinal  segment.  When  two 
pieces  of  food  were  held  on  wires  one  to  the  right  and  the  other 
to  the  left,  or  one  above  and  the  other  below  the  line  of  regard 
both  pieces  were  secured,  but  only  after  considerable  fumbling 
and  after  making  numerous  futile  attempts  to  reach  the  food. 
Grapes  rolled  into  the  cage  were  searched  for  and  secured  only 
after  they  had  been  hit  by  one  of  the  fumbling  hands  in  their  ap- 
parently rambling  movements.  Seven  lima  beans  were  placed 
on  the  glass  plate  in  the  form  of  a  hexagon,  and  only  after  much 
fumbling  were  these  obtained.  A  small  very  bright  red  tomato, 
placed  60  cm.  from  the  animal,  was  not  noticed  for  two  or  three 
minutes,  but  after  that  time  it  appeared  to  me  that  the  animal 
had  sensed  its  presence,  whereupon  she  began  a  search  for  the 
tomato  finally  securing  it  after  about  40  seconds.  Grapes  and 
beans  lying  outside  the  cage  were  secured  with  difficulty ;  usually 
the  animal  made  a  movement  in  the  general  direction  of  the  food 
and  then,  not  finding  it,  swung  the  arm  and  hand  until  some- 
thing was  touched.  In  taking  food  presented  at  the  ends  of 
wires  and  from  the  floor  it  was  noted  that  the  first  movement  was 
in  the  general  direction  of  the  food,  and  when  the  food  was  not 
secured  by  this  first  movement  (as  was  usually  the  case)  the 
monkey  drew  the  hand  backwards,  peered  at  the  food  for  a  second 
or  so  and  tried  again.  The  errors  of  movement  (i.  e.,  the  dis- 
tance between  the  food  and  the  tips  of  the  searching  fingers) 
averaged  about  2  cm.,  and  the  record  of  nine  different  attempts 
show  that  these  errors  were  in  all  possible  directions,  too  far 
from,  too  near,  to  the  right  of  and  to  the  left  of  the  food. 

On  the  succeeding  days  the  inaccuracies  in  adjustment  became 
less  noticeable,  and  thirteen  days  after  the  operation  they  were 
to  be  discovered  only  by  careful  observation.  On  this  day  the 
animal  was  examined  by  Dr.  F.  M.  Barnes,  Jr.,  who  wrote  the 
following  notes;  "The  animal  is  quite  active,  moving  about  the 
cage  and  taking  notice  of  all  about  it.  She  does  not  seem  especial- 


EXPERIMENTAL  RESULTS  87 

ly  frightened  but  moves  quickly  at  very  slight  noises.  It  seems 
impossible  to  make  the  slightest  movement  in  front  of  the  cage 
without  attracting  the  animal's  attention.  When  a  pencil  is 
pointed  at  her  through  the  wires  of  the  cage  she  strikes  at  it  with 
her  right  hand;  the  aim  is  true  and  sometimes  she  grasps  the 
pencil  and  pulls  it.  Vision  for  objects  (wires  and  rods)  on  both 
sides  and  from  above  and  below  is  acute.  A  piece  of  potato  was 
placed  under  a  watch  glass  and  introduced  into  the  cage.  The 
animal  grabbed  for  it  several  successive  times,  then  with  both 
hands  found  the  edges  of  the  watch  glass  and  made  an  attempt 
to  turn  it  over.  A  piece  of  potato  was  placed  in  a  small  glass 
crystallizing  dish,  which  the  animal  seized,  turned  over  quickly 
but  did  not  use  the  hand  to  secure  the  food  but  inserted  the 
mouth.  Another  trial  under  similar  conditions,  but  the  potato 
dropped  to  the  floor  when  the  glass  was  introduced :  the  monkey 
picked  up  the  dish,  held  it  to  the  mouth  and  tried  to  get  food  from 
it  leaving  the  food  on  the  floor  unnoticed.  When  the  dish  and  the 
watch  glass  were  placed  in  the  cage  she  took  up  both  even  though 
no  food  was  in  them.  Blocks  of  apple  and  carrot  thrown  into 
the  cage  are  generally  picked  up  quickly  and  accurately.  Often 
she  seems  to  look  directly  at  a  piece  of  food  for  some  time  before 
taking  it  up.  She  frequently  misses  a  piece  of  food  by  5  to  8 
cm.,  and  on  groping  gets  farther  off.  With  several  different 
kinds  of  food  thrown  into  the  cage  she  does  not  appear  to  dis- 
criminate but  picks  up  ginger  snap  along  with  the  apple  and  only 
after  having  conveyed  the  ginger  snap  to  the  mouth  does  she  re- 
ject it.  She  often  picked  at  a  knot  hole  in  the  floor  of  the  cage 
and  appeared  to  attempt  to  pick  it  up.  Vision  does  not  seem  dis- 
turbed when  tested  by  rods  approached  from  the  four  retinal 
quadrants ;  the  upper  segment  may  have  some  dimness,  for  there 
is  some  inability  to  discriminate  and  to  pick  up  food  from  the 
bottom  of  the  cage.  There  is  some  incoordination  of  movement 
in  prehension.  It  appears  as  if  the  animal  does  not  discriminate 
between  the  colors,  white,  red,  and  brown."  The  last  conclusion 
does  not  appear  to  me  to  follow  from  the  results  of  the  experi- 
ments, for  although  the  animal  in  its  normal  condition  took  fruit 
in  preference  to  bread  and  ginger  snap  both  the  latter  kinds  of 
food  were  eaten  with  apparent  enjoyment.  It  also  appears  that 


88 


SHEPHERD   IVORY   FRANZ 


the  incoordination  of  movement  in  grasping  the  particles  of  food 
may  have  given  the  impression  that  there  is  no  ability  to  dis- 
criminate, for  in  tests  with  other  animals  it  was  found  that  when 
pieces  of  food  were  widely  separated  the  movement  was  always 
made  in  the  proper  direction,  although  the  food  was  not  imme- 
diately secured,  but  that  when  the  food  pieces  were  close  together 
the  animal  at  times  managed  to  get  the  wrong  piece  and  often  to 
take  two  pieces  at  once.  It  would  perhaps  be  better  to  make 
a  statement  of  the  action  rather  than  to  draw  the  conclusion : 
the  animal  picked  up  indiscriminately  pieces  of  white,  brown 
and  red  food,  although  when  these  pieces  were  conveyed  to  the 
mouth  only  the  red  were  usually  eaten. 


FIGS.  68,  69,  70  and  71.  Monkey  6.  Lateral  and  mesial  aspects  of  the 
hemispheres,  showing  the  extent  of  the  lesion  produced  by  cauterization  of 
the  pia  and  cortex.  Slightly  reduced.  Traced  from  photographs. 

The  animal  was  killed  two  days  later,  without  having  shown 
any  further  variations  in  vision  or  other  sensory  functions.  At 
the  autopsy,  the  brain  was  found  adherent  to  the  dura  and  to  the 
scalp  over  the  site  of  the  trephine  buttons,  and  it  was  with  diffi- 


EXPERIMENTAL  RESULTS 


89 


culty  separated  from  the  scalp.  The  brain  weighed  94  grams. 
The  occipital  lobes  were  placed  in  alcohol  for  examination  by 
the  Nissl  method  and  the  remainder  of  the  brain  was  hardened 
in  bichromate  for  examination  by  the  method  of  Donnagio. 


FIGS.  72,  73,  74,  75,  76  and  77.  Monkey  6.  Frontal  sections  of  cerebral 
hemispheres,  with  drawings  of  the  histological  examination.  Slightly  en- 
larged. Edinger  drawing  apparatus. 

The  results  of  the  operation  are  to  be  found  represented  in 
figures  68  to  77.  It  will  be  seen  that  in  this  animal  the  cortex 
surrounding  the  calcarine  fissure  has  not  been  disturbed  to  any 
extent  and  that  the  destruction  of  the  visual  cortex  beyond  the 
calcarine  region  has  been  very  extensive.  Such  a  lesion  should 
have  produced  a  very  decided  visual  defect  if  this  area  were 
concerned  with  perceptions  or  sensations  of  a  visual  character, 
for  with  the  exception  of  the  cortex  along  the  calcarine  fissure 
practically  all  the  so-called  visual  cortex  has  been  affected. 

The  report  of  Dr.  Lafora  on  the  examination  of  the  micro- 
scopical sections  is  as  follows:  "Monkey  6.  Cauterization  of 
the  brain,  frontal  sections,  Nissl  method.  On  the  left  side  the 
cortex  along  the  calcarine  fissure  is  not  affected  excepting  the 
oral  side  of  the  superior  ramification,  at  the  extreme  end  of  the 
occipital  lobe.  The  lesion  on  the  right  closely  corresponds  with 


90  SHEPHERD   IVORY  FRANZ 

that  on  the  left,  but  there  is  a  slight  hemorrhage  near  the  cal- 
carine  fissure."  The  examination  by  the  method  of  Donnagio 
has  not  yet  been  completed. 

Monkey  7.  This  animal  was  trained  to  discriminate  the  four 
colors.  At  first  the  animal  did  not  seem  to  discriminate  between 
the  bitter  breads,  and  for  the  first  eight  days  of  the  experiments 
ate  the  bitter  (green  and  yellow)  breads,  as  well  as  the  sweet 
(red  and  blue),  even  though  at  times  the  green  and  yellow  were 
rolled  in  quinine  and  the  animal  had  previously  been  thoroughly 
fed  and  the  cheek  pouches  were  filled  with  food.  Oct.  27,  the 
eighth  day  of  the  experiments,  she  refused  the  green  and  yellow 
breads  most  of  the  time,  and  on  the  following  three  days  did  not 
take  the  bitter  breads  once.  On  Nov.  i  and  3,  she  took  the  green 
bread  once  each  day,  but  in  later  tests  (November  5,  20,  25,  and 
28),  after  intervals  of  one,  fourteen,  four  and  two  days,  re- 
spectively, she  made  no  mistakes. 

The  operation  was  performed  Nov.  28.  Both  occipitals  were 
cut  away  by  a  frontal  incision.  On  cutting  the  left  occipital, 
the  right  eye  was  observed  to  rotate  slowly  upwards  and  to  the 
right,  and  this  movement  appeared  to  be  concomitant  with  the 
slow  drawing  movement  of  the  knife.  The  monkey  reacted  well 
after  the  operation,  and  two  hours  after  having  been  placed 
in  her  cage  was  noticed  to  be  busily  engaged  examining  all  parts 
of  it.  Her  movements  were  rather  slow,  but  they  seemed  to 
be  executed  well  and  precisely.  No  reaction  to  noises,  loud  or 
soft,  e.  g.,  whistling,  clapping  hands,  etc.,  was  observed,  but  any- 
thing moving  about  the  cage  attracted  her  attention.  The  ob- 
servation cage  had  been  placed  in  a  room  to  which  the  animal 
was  not  accustomed,  and  she  repeatedly  went  to  the  5  cm.  open- 
ing at  the  back  and  peered  through  it.  Eight  hours  later  the 
animal  was  found  asleep,  but  when  awakened  seemed  to  be  in 
the  same  state  as  that  just  described,  curiously  examining  all 
things,  following  with  the  head  and  eyes  moving  objects,  etc. 

One  day  after  the  operation,  a  few  tests  with  colored  breads 
were  made.  In  these  the  animal  selected  the  red  and  blue  and 
disregarded  the  green  and  yellow,  but  in  each  test  did  not  take 
both  sweet  pieces.  The  movements  were  quick  and  accurate. 
She  picked  up  food  from  the  floor  of  the  cage,  accurately  reached 


EXPERIMENTAL  RESULTS  91 

up  to  the  top  of  the  cage  and  secured  small  pieces  of  sugar  and 
other  food  which  were  held  there.  She  was  tested  with  the 
colored  breads  with  the  same  result  noted  above.  She  was  then 
placed  in  the  cage  with  the  male  Monkey  8,  whom  she  picked 
over  for  fleas,  dandruff,  etc.,  in  a  perfectly  normal  manner.  Dur- 
ing this  procedure  she  was  seen  to  stop,  and  make  a  quick  move- 
ment, thereby  catching  a  fly. 

Two  days  after  the  operation  (Nov.  30),  ten  tests  with  the 
colored  breads  showed  perfect  retention  of  the  ability  to  discrim- 
inate, and  on  the  following  day  ( Dec.  i )  the  following  results 
were  obtained:  Tests  1-6,  ate  all  four  pieces;  7,  ate  the  red,  blue 
and  yellow,  and  disregarded  the  green;  8,  ate  red,  blue  and  yel- 
low, but  did  not  pick  up  the  green;  9,  and  10,  ate  the  red  and 
blue,  but  did  not  take  the  yellow  and  green.  Two  days  later  she 
took  red  and  blue  in  the  first  trial  but  refused  to  take  more,  and 
on  the  following  day  (Dec.  4)  refused  to  work.  Two  days 
later  in  ten  trials  she  ate  all  four  pieces  presented  to  her. 

During  the  succeeding  days  no  abnormality  of  vision  was  de- 
tected; the  movements  of  grasping  objects  presented  in  any  part 
of  the  visual  field  were  accurate  and  quick,  and  there  were  no 
observable  errors  in  discrimination.  A  second  operation  was 
determined  upon  but  deferred  for  about  four  months  and  a  half 
(April  1 6).  During  the  intervening  period  the  monkey  was  re- 
turned to  the  large  cage  with  a  normal  monkey,  and  so  far  as  it 
was  observed  acted  in  a  perfectly  normal  manner.  At  the  end 
of  about  four  months  the  memory  for  the  colored  breads  was 
tested  and  found  to  be  defective.  On  the  first  day  after  this 
second  series  (March  29),  she  took  all  four  pieces  in  the  five 
tests,  but  two  days  later  made  only  two  mistakes  in  ten  trials. 
During  the  next  two  weeks  the  monkey  was  given  tests  on  three 
days,  with  intervals  of  5  and  7  days  respectively,  in  all  of  which 
the  green  and  yellow  were  disregarded  and  the  red  and  blue 
were  taken.  On  the  day  of  the  second  operation  (April  16)  the 
monkey  took  the  yellow  bread  several  times  and  the  green  once 
in  ten  trials. 

Second  operation,  April  16.  At  the  operation  the  posterior 
portions  of  the  occipital  cortex  were  cauterized.  The  site  of 
the  trephine  openings  made  at  the  time  of  the  first  operation 


92  SHEPHERD   IVORY  FRANZ 

were  distinctly  visible,  the  button  on  the  right  side  was  soft, 
that  on  the  left  was  hard.  New  openings  were  made  slightly 
posterior  to  these,  and  the  old  buttons  were  removed.  It  was 
found  that  the  bridge  of  bone  between  the  two  original  trephine 
openings  had  disappeared,  so  that  when  the  new  trephine  holes 
were  made,  both  occipitals  were  exposed  and  the  bone  opening 
extended  from  one  side  to  the  other.  The  loss  of  blood  at  the 
operation  was  slight  and  the  animal  recovered  from  the  anesthetic 
soon  after  being  taken  from  the  operating  table. 

Fifteen  minutes  after  the  operation  the  monkey  sat  up  in  the 


79 


FIGS.  78  and  79.  Monkey  7.  Lateral  aspects  of  cerebral  hemispheres,  show- 
ing the  extent  of  lesions  produced  at  the  second  operation,  and  the  location 
of  parts  examined  by  histological  methods.  Slightly  reduced.  Traced  from 
photographs. 

cage,  looked  about  in  a  dazed  manner  and  moved  about  slowly. 
An  hour  after  the  operation  she  was  more  nearly  normal.  She 
took  a  piece  of  bread  presented  to  her  through  the  wire  netting, 
moving  forward  about  25  cm.  and  reached  for  the  food  with  an 
error  of  only  about  3  cm.  One  hour  later  she  was  given  a  pea- 
nut, which  she  reached  for  accurately.  She  conveyed  the  peanut 
to  her  mouth,  took  the  nut  out  of  the  shell  and  began  to  strip 
the  red  skin  from  the  nut  in  a  normal  manner.  When  the  shell 


EXPERIMENTAL  RESULTS 


93 


had  been  thrown  away,  the  monkey  took  the  nut  from  her  mouth 
from  time  to  time  when  stripping  the  skin  from  it  and  examined 
it  until  the  skin  had  been  removed.  She  was  given  water  in 
a  saucer,  but  did  not  drink  it  for  an  hour. 

The  day  following  the  operation,  the  animal  appeared  to  be 
normal,  and  two  days  after  the  operation  in  five  tests  with  colored 
breads  she  showed  perfect  discrimination.  At  no  time  was  there 
evidence  of  a  visual  disturbance  as  the  result  of  this  operation. 
The  monkey  was  taken  to  Baltimore,  April  20,  and  exhibited  at 
the  meeting  of  experimental  psychologists,  after  which  it  was 
killed. 


80 


cent 


fcolc. 


cole 


FIGS.  80  and  81.  Monkey  7.  Tracings  from  photographs  of  lower  parts 
of  sections  82,  83,  85,  and  86,  of  rigs.  78  and  79,  showing  extent  of  lesions. 
Slightly  reduced. 

At  the  autopsy  the  areas  of  softening  of  the  cortex  were  dis- 
tinctly noticeable  apparently  extending  over  the  convexity  of  the 


94 


SHEPHERD   IVORY   FRANZ 


occipital  lobes  almost  to  the  parieto-occipital  fissure.  The  results 
of  the  autopsy  and  histological  examinations  are  shown  in  the 
accompanying  figures  (78  to  87).  In  these  it  will  be  seen  that 
the  occipital  poles  have  been  almost  entirely  destroyed,  and  that 
the  destruction  of  the  so-called  visuo-sensory  cortex  is  extreme, 


FIGS.  82,  83,  84,  85,  86  and  87.  Monkey  7.  Horizontal  sections  of  cerebral 
hemispheres,  with  results  of  histological  examinations,  showing  the  amount 
of  destruction  by  cauterization.  Slightly  enlarged.  Edinger  drawing  appa- 
ratus. 

with  the  exception  of  that  surrounding  the  calcarine  fissure. 
The  report  of  Dr.  Lafora  on  the  brain  is  as  follows : 
"Monkey  7.  Cauterization  of  the  brain :  Nissl  method;  hori- 
zontal sections.  On  the  right  side  the  calcarine  area  is  affected 
only  at  the  superior  branch  of  the  fissure,  but  the  cortex  at  the 
occipital  pole  is  almost  entirely  destroyed.  On  the  left  side 
there  is  a  marked  destruction  of  the  most  posterior  part  of  the 
occipital  pole  with  an  irritation  lesion  of  the  pia  around  this 
lesion.  In  the  superior  branch  of  the  calcarine  fissure  there  are 
some  lesions."  The  effects  of  the  first  operation  (section)  were 
not  determined  by  the  histological  method  employed,  and  at  the 
time  of  writing  no  examination  of  fibres  had  been  made. 


EXPERIMENTAL  RESULTS  95 

Monkey  8.  This  animal  was  trained  to  discriminate  red  and 
yellow  breads.  The  training  began  Oct.  20  and  continued  until 
Nov.  26,  with  intervals  of  2,  6,  and  n  days — after  the  habit 
had  been  formed.  At  the  latter  date,  the  animal  had  indicated 
the  ability  to  discriminate  the  red  from  the  yellow,  and  to  retain 
this  over  a  period  of  eleven  days. 

The  operation  of  cutting  both  occipitals  was  performed  Nov. 
26.  There  was  considerable  hemorrhage  which  was  controlled 
by  hot  compresses.  There  was  also  considerable  shock  from  the 
operation,  and  the  monkey  did  not  recover  from  the  general  de- 
fects for  several  hours.  Immediately  after  the  operation  it  was 
noted  that  the  pupils  were  slightly  dilated,  but  were  equal.  A 
slight  nystagmus  was  suspected  but  at  times  this  did  not  appear 
to  be  present,  and  it  was  impossible  to  decide  whether  or  not  the 
movement  was  partly  voluntary.  The  eyes  appeared  to  be  rotated 
toward  the  right.  When  placed  in  the  observation  cage  the  ani- 
mal was  laid  on  the  left  side  but  it  kept  its  head  raised  from  the 
floor,  and  there  was  a  slight  tremor  of  the  head.  Three  hours 
after  the  operation  the  animal  appeared  lethargic,  its  general 
movements  were  slow  and  apparently  performed  only  with  great 
effort  and  without  much  force.  When  a  stick  was  thrust  through 
the  wire  netting  the  monkey  reached  for  it  slowly  but  accurately. 
It  grasped  the  stick,  carried  it  toward  its  mouth  and  bit  it,  making 
these  movements  slowly  and  pulling  and  biting  the  stick  without 
any  display  of  energy.  The  wound  or  the  bandage  was  appa- 
rently irritating,  for  the  monkey  continually  scratched  at  the 
bandage  when  its  attention  was  not  attracted  by  and  directed 
to  objects  held  by  the  experimenter.  The  animal  grasped  food 
accurately  but  slowly,  and  picked  up  food  which  was  placed  on 
the  floor  of  the  cage,  even  when  at  the  farther  end  (about  75 
cm.  distance).  When  a  prune  was  held  10  cm.  in  front  of  the 
cage,  the  monkey  put  its  hand  through  the  mesh  of  the  wire 
netting  slowly  but  accurately,  grasped  the  prune,  drew  it  in, 
and  immediately  ate  it. 

By  the  following  day  the  dilation  of  pupils  and  the  nystagmus 
(suspected)  had  disappeared.  The-  general  movements  were 
more  quickly  performed,  and  the  accuracy  was  the  same  as  that 
following  the  operation.  General  tests  with  food  were  made,  the 


g6  SHEPHERD   IVORY  FRANZ 

animal  reacting  in  a  normal  manner,  selecting  pieces  of  food 
from  a  number  placed  on  the  floor  of  the  cage,  and  rejecting 
those  things  which  were  of  no  value,  and  also  those  which  it 
was  known  not  to  prefer,  e.  g.,  plain  bread.  No  special  tests  of 
color  were  made  on  this  day. 

Two  days  after  the  operation  the  animal  appeared  able  to  see 
and  to  discriminate  all  kinds  of  food  and  other  objects  held  in 
any  part  of  the  visual  field,  but  when  tested  with  the  colored 
breads  (which  experiment  was  performed  first  on  this  day  when 
the  animal  was  hungry),  the  animal  reached  for  and  took  both 
kinds  of  bread.  It  appeared  at  this  time  that  the  animal  had 
lost  the  ability  to  discriminate  the  colors  red  and  yellow  in  the 
bread  test,  although  when  tested  with  other  foods  of  similar 
color  (carrot,  tomato,  yellow  turnip),  there  was  no  hesitation 
in  selecting  the  red  (tomato)  and  of  selecting  these  vegetables 
instead  of  the  red  and  yellow  breads. 

No  special  tests  were  made  on  the  following  day — the  animal 
appearing  to  be  in  the  same  condition  as  that  just  mentioned. 
However,  on  the  following  day,  four  days  after  the  operation, 
the  animal  was  first  tested  with  foods  placed  in  different  parts 
of  the  cage,  with  foods  held  in  different  visual  segments  and 
with  foods  outside  the  cage,  the  animal  reacting  at  all  times  fairly 
quickly  and  accurately  and  at  no  time  making  errors  in  adjust- 
ment of  more  than  one  cm.  After  these  tests  (the  monkey 
being  not  absolutely  hungry)  the  tests  with  colored  bread  were 
made,  and  in  the  ten  trials  the  monkey  did  not  select  the  yellow 
bread  once,  and  took  only  the  red.  It  appears  likely,  therefore, 
that  the  errors  made  on  the  second  day  following  the  operation 
may  have  been  due  to  hunger,  any  food  being  preferable  to  the 
animal  than  no  food.  The  results  of  this  test  are  particularly 
instructive,  especially  when  they  are  considered  in  conjunction 
with  the  results  of  the  similar  tests  with  Monkey  7.  With 
Monkey  7,  it  will  be  remembered  (page  91),  the  animal  dis- 
criminated the  colored  breads  perfectly  on  the  second  day  after 
the  operation,  but  on  the  third  day  it  appeared  to  have  lost  the 
ability.  The  latter  result,  in  my  opinion,  is  to  be  explained  as 
due  to  the  fact  that  these  tests  were  performed  at  the  beginning 
of  the  series  of  observations  on  that  day,  when  the  monkey  had 


EXPERIMENTAL  RESULTS 


97 


not  been  fed  for  24  hours,  and  when  it  was  very  hungry.  A 
similar  conclusion  was  drawn  by  me  in  regard  to  the  monkey  now 
under  consideration.  In  the  first  tests  of  discrimination  reten- 
tion, the  experiments  were  performed  after  a  period  of  food 
abstinence,  and  the  conclusion  is  drawn  that  the  taking  of  both 
foods  at  this  time  was  due  to  the  extreme  hunger  of  the  animal. 
That  this  conclusion  (or  a  similar  one)  is  correct  is  evidenced  by 
the  fact  that  the  discrimination  of  the  breads  on  the  fourth  day 
following  the  operation  was  perfect  from  the  first  trial,  and  there 
was  no  mistake,  not  even  that  of  touching  the  yellow  pieces  of 
bread.  On  the  succeeding  days  the  discrimination  was  perfect. 
The  animal  was  killed  eight  days  after  the  operation  to  determine 
the  pathological  condition. 


FIGS.  88,  89,  90  and  91.  Monkey  8.  Lateral  and  mesial  aspects  of  the 
hemispheres,  showing  the  course  of  the  knne  cuts  and  indicating  the  ap- 
proximate extents  of  the  lesions.  Made  from  photographs.  Slightly  reduced. 

At  the  autopsy,  the  brain  was  found  to  be  in  a  healthy  condi- 
tion. The  positions  of  the  insertion  of  the  knife  into  the  hemi- 
spheres were  visible,  and  it  appeared  that  the  knife  had  separated 
most  of  the  occipital  (visuo-sensory)  lobe  from  the  anterior  part 
of  the  brain.  The  appearance  of  the  brain  is  shown  in  figs.  88  to 


SHEPHERD   IVORY  FRANZ 


FIG.  92.    Monkey  8.    Gross  appearance  through  part  of  one  section  of  the 
left  hemisphere.     Free  hand,  slightly  enlarged. 


FIGS.  93,  94,  95  and  96.  Monkey  8.  Microscopical  appearance  of  frontal 
sections,  showing  degenerations  as  indicated  by  the  method  of  Marchi.  On 
the  right  side  only  part  of  one  section  was  preserved,  which  probably  corre- 
sponds with  section  95  on  the  left.  Edinger  drawing  apparatus,  slightly  en- 
larged. 


EXPERIMENTAL  RESULTS  99 

91,  in  which  are  indicated  the  general  courses  of  the  knife  cuts. 
The  brain  weighed  107  grams. 

The  brain  was  prepared  for  examination  by  the  Marchi  method 
to  show  the  fiber  degenerations,  and  at  the  time  of  the 
autopsy  a  drawing  was  made  of  one  of  the  gross  sections  on  the 
left  side,  in  which  there  appeared  to  be  an  extensive  hemorrhage. 
This  is  shown  in  fig.  92.  At  the  time  of  the  autopsy  the  right  side 
was  cut  in  the  same  way  as  the  left,  but  none  of  the  sections) 
showed  the  appearance  indicated  on  the  left.  After  hardening, 
however,  each  of  the  three  sections  on  the  right  was  again  di- 
vided and  an  appearance  similar  to  that  on  the  left  was  found 
on  this  side.  In  gross  section  the  hemorrhage  on  the  right  side 
appeared  to  be  more  extensive  than  that  on  the  left,  including 
practically  all  of  the  white  matter.  At  this  time  no  sketch  was 
made  of  the  extent  of  the  lesion  on  the  right  side,  and  this  is 
especially  unfortunate  on  account  of  the  later  accidental  de- 
struction of  most  of  the  posterior  portions  of  this  hemisphere. 
In  the  process  of  hardening  and  infiltration,  all  of  the  pieces  ot 
the  right  hemispheres,  with  the  exception  of  part  of  one,  dis- 
integrated in  the  celloidin,  leaving  a  muddy  residue  and  this  part 
of  the  brain  was,  therefore,  not  examined  histologically.  The 
part  of  the  right  side  which  did  not  disintegrate  probably  corre- 
sponds with  section  95  on  the  left  side,  although  this  is  not  certain 
because  so  much  has  been  lost. 

Following  is  the  report  of  Dr.  Lafora  on  the  microscopical 
findings:  "Monkey  8.  Section  of  the  white  substance,  Marchi 
method  by  Dr.  Achucarro.  On  the  left  side  the  degeneration  is 
not  very  well  marked  because  of  the  short  time  the  animal  was 
permitted  to  live  after  the  operation  (eight  days).  Many  fat 
drops,  however,  are  observed  in  the  sections,  and  they  are  more 
abundant  in  the  radiatio  optica,  and  in  the  fasculus  longitudinal  is 
inferior.  In  the  white  substance  near  the  cortex  many  fat  drops 
were  also  observed.  From  the  study  of  the  degenerated  fibers, 
it  is  not  certain  that  all  the  optical  fibers  on  this  side  have  been 
destroyed,  but  that  many,  perhaps  most,  have  been  affected  by 
the  degeneration,  there  can  be  no  doubt.  The  section  on  the 
right  side  shows  about  the  same  degree  of  degeneration  as  those 
on  the  left,  and  although  none  of  the  parts  can  be  accurately  dis- 


ioo  SHEPHERD  IVORY  FRANZ 

tinguished,  it  appears  that  this  section  corresponds  with  95  on  the 
left  side." 

The  report  of  Dr.  Lafora  indicates  a  marked  destruction  of 
fibers  on  the  left  side  which  corresponds  closely  with  what  is  to 
be  expected  from  the  extent  of  the  hemorrhages  indicated  in 
figure  92.  It  is  especially  unfortunate  that  in  this  case  the 
hemorrhagic  appearance  on  the  right  side  was  not  drawn  and  that 
the  pieces  of  this  hemisphere  disintegrated  and  prevented  a  care- 
ful histological  examination.  Sufficient  is  shown  in  the  part  of 
the  right  side  to  show  the  marked  degree  of  degeneration  and  to 
indicate  an  amount  of  destruction  of  fibers  (fatty  degeneration) 
corresponding  with  that  on  the  left. 

DISCUSSION  OF  RESULTS 

The  observations  recorded  in  the  foregoing  pages  show  that 
destruction  of  parts  of  the  so-called  visuo-sensory  cortex  is  ac- 
companied by  derangements  of  a  varied  character,  but  of  minor 
degree  when  compared  with  those  recorded  by  most  previous  in- 
vestigators. Only  one  animal  showed  the  marked  visual  dis- 
turbances which  are  comparable  with  those  which  have  been 
reported  by  Munk,  by  Ferrier,  by  Schafer  and  by  others,  and  in 
this  case  the  amount  of  destruction  was  much  greater  than  in  any 
other  animal,  and  the  disturbance  did  not  become  marked  for 
some  days  after  the  operation. 

The  effects  of  the  operations  on  the  animals  may  be  grouped 
into  four  general  classes:  the  general  appearance  of  the  eyes 
and  the  ability  of  the  eyes  to  move,  the  fields  of  vision,  the  dis- 
crimination of  objects  and  of  colors,  and  the  ability  of  visual- 
motor  coordination.  In  no  case  were  all  of  these  elements  af- 
fected, and  in  most  of  the  animals,  as  has  been  noted,  the  amount 
of  disturbance  was  slight  and  was  often  limited  to  one  of  the 
elements  just  enumerated. 

Some  of  the  animals  showed  pupillary  disturbances  imme- 
diately after  the  operation.  Three  (monkeys  I,  2,  and  8)  had 
dilated  pupils,  but  it  is  not  possible  to  say  definitely  whether  this 
condition  was  due  to  the  effects  of  the  operation  as  such  or  to 
the  anesthetic.  It  is  well  known  that  following  operations  on 


DISCUSSION   OF   RESULTS  101 

other  parts  of  the  body  there  may  be  pupillary  disturbances,  and 
these  have  been  taken  to  indicate  the  effects  of  the  anesthetic. 
In  these  monkeys  we  are  also  justified  in  concluding  that  the 
dilation  is  the  effect  of  the  anesthetic,  although  in  one  case  it 
must  be  remembered  that  the  pupils  were  not  equally  dilated. 
In  the  case  just  mentioned  the  left  pupil  was  decidedly  larger 
than  the  right,  and  this  may  have  been  a  sequel  of  the  operation, 
although  it  is  not  possible  to  determine  this  with  exactitude.  The 
fact  that  the  other  four  animals  did  not  show  pupillary  dis- 
turbances would  lead  me  to  suppose  that  in  the  cases  of  mon- 
keys i,  2,  and  8  we  had  to  deal  with  a  chance  condition,  not  with 
one  intimately  associated  with  the  destruction  of  the  occipital 
cortex. 

It  may  be  different,  however,  with  the  other  eye  movements. 
Immediately  after  the  operation  monkey  2  showed  a  tremor  of 
the  eyelids,  and  this  was  not  the  effect  of  the  anesthetic,  but  an 
effect  undoubtedly  due  to  the  operation  on  the  occipitals.  After 
the  second  operation  on  monkey  i,  I  observed  that  its  eyes  were 
turned  inwards  and  upwards,  and  after  the  operation  on  monkey 
8  the  eyes  were  directed  toward  the  right.  In  addition,  monkey 
8  showed  a  nystagmus  following  the  operation,  this  condition 
persisting  for  some  time.  It  was  also  observed  that  at  the  time 
of  the  operation  on  monkey  7,  the  occipital  lobe  being  cut  in  this 
operation,  the  right  eye  slowly  rotated  upwards  and  turned 
toward  the  right  at  the  time  the  section  was  being  made. 

These  oculomotor  disturbances  were  noticeable  in  only  four  of 
the  animals  upon  which  operations  were  performed,  and  it  can  not 
be  concluded  that  they  have  a  direct  bearing  upon  the  problem 
of  the  functions  of  this  area.  It  is  known  that  stimulation  of  the 
occipital  lobes  produces  movements  of  the  eye  balls  and  of  the 
intrinsic  eye  muscles,  and  it  is  possible  that  the  motor  defects 
are  due  to  the  destruction  of  the  mechanism  which,  by  its  activ- 
ity, produces  corresponding  movements.  That  the  defects  per- 
sisted for  only  a  few  hours  or  a  few  days  indicates  however,  that 
the  phenomena  are  due  to  an  irritation  rather  than  to  a  paralyzing 
effect,  and  it  is  pertinent  to  consider  the  slow  upward  rotation 
of  the  eye  in  monkey  7  at  the  time  of  the  section  as  evidence  of 
this.  This  condition  corresponds  with  what  has  been  found  by 


102  SHEPHERD  IVORY  FRANZ 

some  investigators  upon  stimulation  of  the  occipital  cortex,  and 
since  it  corresponds  also  with  the  more  lasting  (although  transi- 
tory) effects  in  monkeys  i  and  8,  it  is  at  present  justifiable  to 
conclude  that  it  is  an  irritative  effect. 

The  general  statement  may  be  made  that  the  operations  did 
not  produce  any  alteration  in  the  ability  of  the  animals  to  dis- 
criminate objects,  for  in  all  cases  the  animals  were  able  to  select 
food  and  to  pick  over  the  floor  of  the  cage  for  objects  which 
were  later  conveyed  to  their  mouths.  In  only  one  case  was  there 
any  difficulty,  and  this  animal  did  not  show  this  difficulty  im- 
mediately after  the  operation,  but  only  after  a  week.  That  all  the 
animals  which  had  previously  been  trained  to  discriminate  colored 
breads  were  able  to  discriminate  them  after  the  operation  is 
evident  from  the  records  of  the  individual  cases.  It  was  unfor- 
tunate that  the  tests  of  color  vision  after  the  operation  could 
not  be  performed  in  exactly  the  same  way  as  they  were  performed 
before  the  operation,  but  the  results  which  were  obtained  with 
the  new  methods  speak  plainly  for  the  retention  of  the  color  dis- 
crimination. In  most  of  the  cases  the  color  tests  were  delayed 
'  for  at  least  two  days  following  the  operation,  so  that  any  general 
shock  effects  of  the  operation  might  pass  away  and  so  that  the 
animal  should  be  in  as  normal  a  condition  as  possible  for  the 
tests.  Even  with  this  amount  of  time  it  was  sometimes  found 
that  the  animal  would  not  take  the  colored  breads,  and  the  tests 
had  to  be  made  on  a  succeeding  day.  Monkey  I  discrim- 
inated the  colored  breads  two  days  after  the  first  operation,  and 
three  days  after  the  second  operation.  Monkey  2  discriminated 
the  colored  breads  three  days  after  the  operation.  Monkey  4 
discriminated  the  colored  breads  two  days  after  the  operation; 
monkey  5  did  not  work  well  during  the  first  few  days  after 
the  operation,  but  showed  color  discrimination  ability  on  the  sixth 
day,  and  similarly  with  monkey  6.  Monkey  8  discriminated  the 
colored  breads  on  the  fourth  day,  and  monkey  7  was  tested  on 
the  same  days  as  the  operations  (two  of  which  were  performed 
on  this  animal)  and  both  times  was  able  to  select  the  proper 
colors.  From  these  results  it  can  not  be  doubted  that  the  ability 
to  discriminate  colors  remained  after  the  extensive  operations 
which  were  performed,  and  it  appears  plain  that  the  parts  of 


DISCUSSION  OF  RESULTS  103 

the  brain  which  were  destroyed  have  not  the  function  of  color 
perception  or  of  color  discrimination. 

In  addition  to  the  special  color  tests,  general  tests  were  made 
with  each  animal,  and  the  results  of  these  general  tests  are  in 
agreement  with  the  special  tests  of  color  which  were  made  with 
the  breads.  Even  immediately  after  the  operation,  if  the  animal 
was  sufficiently  recovered  from  the  effects  of  the  anesthetic, 
there  remained  a  marked  ability  to  discriminate  colored  foods, 
and  in  most  cases  the  judgment  of  the  animal  was  unerring. 
When  cotton  wool,  rolled  into  balls,  was  introduced  into  the 
cages,  the  animals  at  times  picked  up  this  material  and  placed  it 
in  the  mouth,  but  this  is  exactly  what  a  normal  monkey  does, 
and  the  fact  is  not  evidence  of  a  lack  of  color  discrimination  or 
a  lack  of  discrimination  of  different  foods.  The  selection  of  the 
pieces  of  melon  which  in  color  closely  resembled  some  of  the 
green  pieces  of  bread,  but  did  not  resemble  them  in  texture 
(the  visual  quality  of  which  is  uncertain),  the  selection  of  tomato 
instead  of  the  red  bread,  and  the  selection  of  different  foods 
from  each  other,  as  shown  particularly  in  the  accounts  of  the 
actions  of  monkeys  3,  4,  6,  and  8,  all  indicate  that  the  visual 
discrimination  of  these  animals  remained  approximately  normal. 
That  the  discrimination  ability  was  not  alone  that  of  color  is 
shown  by  the  results  with  monkey  3,  which  had  been  trained  to 
discriminate  different  sizes.  This  animal,  it  will  be  recalled,  re- 
tained this  ability  after  the  operation,  and  it  can  not  be  taken 
as  evidence  other  than  that  for  the  retention  of  the  general  abil- 
ity of  visual  discrimination. 

It  would  have  taken  too  long  a  time  to  detail  for  each  animal 
all  the  observations  which  indicated  the  normal  amount  of  dis- 
crimination ability,  but  in  addition  to  the  observations  which  have 
been  recorded  above,  and  others  which  have  been  contained  in 
the  individual  case  histories,  it  may  be  well  to  indicate  a  few 
other  facts  which  were  observed.  Whenever  the  door  of  the  ob- 
servation cage  was  opened  the  animal  immediately  walked  out. 
In  only  one  case  was  this  discrimination  ability  disturbed,  in 
monkey  5,  and  this  animal  showed  at  the  same  time  an  almost 
total  loss  of  visual  ability.  When  the  operated  animal  was  in- 
troduced into  a  cage  with  a  normal  animal  it  immediately  walked 


104  SHEPHERD  IVORY  FRANZ 

over  to  the  second  animal,  picked  him  or  her  over  for  dandruff, 
and  acted  exactly  like  a  normal  unoperated  monkey.  In  some 
cases  when  a  male  operated  animal  had  been  introduced  into  a 
cage  with  a  female  normal  animal,  he  immediately  mounted  the 
female  for  sexual  congress.  It  was  found  possible  to  fool  an 
animal  once  or  twice  with  cotton  wool,  but  not  more  than  this 
number  of  times,  and  this  fact  indicates  either  the  retention  of 
the  discrimination  ability  it  previously  had  or  the  retention  of 
the  general  ability  to  learn  very  rapidly  to  discriminate  particular 
objects.  Whichever  conclusion  is  considered  correct  makes  little 
difference,  for  both  indicate  a  high  degree  of  discrimination 
ability.  When  food  wrapped  in  papers  or  small  wads  of  paper 
were  introduced  into  the  cages,  the  operated  animals  did  not  place 
the  covered  food  or  the  wads  of  paper  into  the  mouth,  but  pulled 
away  the  paper  from  the  food,  or  pulled  apart  the  wad  of  paper. 
In  both  cases  there  was  a  discrimination  of  the  paper  from  food, 
for  it  was  the  habit  of  the  animals  to  place  food  immediately  into 
the  mouth.  When  water  was  placed  in  the  cages,  most  of  the  ani- 
mals immediately  stooped  down  to  the  dish  and  drank.  In  this 
experiment  there  must  have  been  the  retention  of  a  visuo-motor 
habit,  comprised  of  visual  discrimination  of  the  dish  and  the 
movements  of  the  body,  or  there  must  have  been  a  very  great 
ability  to  discriminate  slight  degrees  of  variation  of  visual  in* 
— ^.  tensities  or  qualities.  The  threatening  of  strangers,  a  common 
trick  with  these  monkeys,  was  shown  in  almost  every  case,  a 
fact  which  also  leads  to  the  conclusion  that  there  was  an  ability 
to  discriminate  me  from  the  other  observers  who  came  to  see  them 
after  the  operations. 

Some  of  the  facts  which  have  been  cited  above  may  also  be 
explained  in  another  way,  viz.,  that  the  discrimination  took  place 
not  because  of  a  visual  discrimination  ability,  but  because  of  a 
smell  discrimination  ability.  This  might  apply  to  the  threatening 
attitude  and  to  the  behavior  with  another  animal,  but  it  can  not 
be  stretched  to  include  all  the  observations  which  have  been 
recorded.  On  the  other  hand,  it  may  be  said  that  the  smell 
component  in  monkey  life  is  not  as  great  as  in  the  carnivora,. 
and  that  these  animals  depend  much  more  upon  vision  and  upon 
hearing.  Smell  ability  may  be  taken  to  explain  the  ability  to- 


DISCUSSION   OF  RESULTS  105 

perform  a  certain  isolated  act,  but  it  can  scarcely  be  taken  to 
explain  the  ability  of  the  animal  to  select  unerringly  five  pieces 
of  melon  or  of  pear  from  among  a  large  number  of  other  pieces 
of  food,  since  the  animal  did  not  place  its  nose  near  the  food 
but  selected  the  food  apparently  by  eye  and  hand. 

The  observations  regarding  the  visual  fields  are  with  the  ex- 
ception of  those  on  monkey  5  consistent.  No  constriction  of  the 
field  was  found  immediately  after  the  operation  in  monkeys  i 
(after  two  operations),  2,  3,  4,  6,  7  (two  operations),  and  8. 
In  some  of  these  animals  there  was  what  might  have  been  taken 
by  a  casual  observer  to  be  a  constriction  of  the  field,  but  in  the 
two  monkeys  in  which  such  a  defect  was  noticed,  it  was  shown  by 
careful  tests  to  be  something  different  from  a  constriction  of  the 
field.  Monkey  3  showed  a  condition  which  has  been  inter- 
preted as  a  diminution  in  visual  acuity,  because  the  animal  was 
able  to  select  things  in  all  fields  but  selected  those  in  some  of  the 
fields  more  readily  than  those  in  others.  Monkey  4  showed  an 
inaccuracy  in  reaching  for  things  held  above  and  below  the  direct 
line,  but  here  we  are  dealing  with  a  complex  condition  rather  than 
with  a  simple  inability  to  see  with  a  certain  part  of  the  retina.  It 
will  be  remembered  that  monkey  6  showed  a  similar  defect  after 
six  days,  but  that  on  the  first  few  days  after  the  operation  there 
was  nothing  to  indicate  a  variation  in  the  field  of  vision. 

The  movement  phenomena  were  similar  in  all  the  animals. 
The  variations  in  movement  are  of  two  kinds,  the  time  and  the 
accuracy.  After  the  first  operation  monkey  i  was  slow  and 
indecisive,  and  in  grasping  movements  made  errors  of  about  2.5 
to  5  cm.  Immediately  after  the  second  operation  the  animal  was 
slow  and  awkward,  the  movements  were  deliberate  and  inaccu- 
rate, and  in  all  these  ways  they  were  quite  unlike  those  of  a  nor- 
mal animal.  Twenty-two  hours  after  the  operation  on  monkey 
2,  it  was  noted  that  the  movements  were  inaccurate,  the  inac- 
curacy lasting  for  about  three  days.  Monkey  3  made  a  number 
of  unsuccessful  attempts  to  grasp  food  which  was  presented  to  it, 
and  for  a  number  of  days  the  adjustment  was  not  like  that  of 
a  normal  animal.  Monkey  4  was  also  inaccurate  in  the  taking 
of  food,  and  monkey  5  was  more  inaccurate  than  any  of  the 
other  animals.  The  last  named  animal  at  first  could  reach  food 


io6  SHEPHERD  IVORY  FRANZ 

within  30  cm.  of  its  body  with  a  fair  degree  of  accuracy,  but 
outside  of  this  area  the  movements  were  slow  and  inaccurate. 
This  animal  eventually  became  blind,  and  the  results  must  be  con- 
sidered apart  from  those  of  the  other  seven  animals  which  re- 
tained their  visual  ability.  All  the  other  animals  showed  inac- 
curacies, slowings  and  apparent  indecisions. 

These  movement  disturbances  were  found  only  in  the  proc- 
esses in  which  the  eyes  had  to  contribute.  They  were  not  found 
with  the  movements  which  were  of  a  reflex  type,  they  were  not 
found  for  movements  which  did  not  require  the  cooperation  of 
the  eyes,  and  no  paralyses  or  pareses  of  the  eyes  or  of  any  of 
the  body  muscles  could  be  determined. 

At  first  glance  it  may  appear  that  we  are  here  dealing  with  a 
visual  disturbance  which  is  evidenced  by  the  lack  of  adjustment 
between  the  visual  sensations  and  the  movements  of  the  arms  and 
hands  in  grasping,  but  a  few  words  may  be  said  upon  this  point. 
Simple  movements,  such  as  those  of  grasping  for  food,  depend 
upon  a  number  of  factors,  which  for  simplicity  we  may  reduce 
to  three — the  sensory,  the  motor,  and  the  associational.  It  is  by 
the  proper  combination  of  these  that  movements  are  performed 
accurately  and  quickly.  If  by  any  means  the  connection  is  in- 
terfered with  (in  the  diaschisis  sense  of  von  Monakow),  the 
end  result  of  the  afferent  stimulation  shows  an  abnormality, 
which  may  vary  from  a  slowness  or  an  inaccuracy  to  an  apparent 
motor  loss.  All  movements  depend  upon  two  primary  factors, 
the  motor  and  the  sensory.  If  one  of  the  two  primary  factors 
be  disturbed,  the  movement  as  a  whole  is  affected.  It  makes  no 
difference  in  a  general  way  which  of  the  two  primary  elements 
be  affected,  except  that  if  the  motor  element  be  destroyed  there 
results  a  total  paralysis.  With  the  incomplete  destruction  of  the 
motor  element  and  with  the  complete  or  incomplete  destruction 
of  the  afferent  or  sensory  element,  the  general  effect  may  be  the 
same,  viz.,  an  inaccuracy,  a  paresis,  or  a  slowing  in  movement. 
In  the  case  of  the  reflexes  the  elimination  of  the  sensory  element 
may  even  produce  a  complete  loss,  just  as  well  as  the  total  elim- 
ination of  the  motor  element.  In  the  present  work,  however,  we 
have  to  deal  with  a  motor  disturbance,  not  with  a  motor  loss, 
and  it  is  apparent  that  the  effects  can  not  be  considered  off-hand 


DISCUSSION   OF   RESULTS  107 

as  purely  motor,  and  on  the  other  hand,  we  must  not  conclude  too 
rapidly  that  the  effects  are  purely  visuo-sensory. 

That  the  disturbances  are  not  of  a  motor  type  is  well  shown 
by  the  fact  that  other  movements  of  a  similar  character  were  not 
affected  at  the  time  of  the  operation.  The  movements  of  con- 
veying food  to  the  mouth  were  accurate  and  quick.  They  were 
exactly  like  those  of  a  normal  animal,  as  far  as  this  could  be 
determined,  and  there  was  no  motor  defect  in  any  of  the  move- 
ments concerned  with  parts  of  the  body  other  than  those  of  the 
hands  and  arms.  The  movements  of  the  head,  of  the  eyes,  and 
even  those  of  the  hands  and  arms,  when  the  animal  did  not  have 
to  deal  with  the  taking  of  food,  and  with  other  movements  in 
which  the  visual  apparatus  was  involved,  were  well  executed, 
and  were  as  quick  as  those  of  a  normal  animal.  It  was  apparent 
that  the  motor  disturbances  were  associated  movement  disturb- 
ances, and  were  those  in  which  the  eyes  were  involved. 

Since  the  movements  which  were  affected  were  those  in  which 
the  eyes  were  concerned  as  one  of  the  afferent  factors,  we  must 
look  to  see  whether  or  not  this  element  (the  eye)  has  been  dis- 
turbed and  has  produced  the  motor  derangement.  We  have,  I 
think,  the  right  to  conclude  that  the  skeletal  muscles  or  the  direct 
motor  control  of  these  muscles  have  not  been  disturbed,  be- 
cause movements  which  did  not  involve  the  visual  element  were 
executed  well.  On  the  other  hand  we  also  know  that  for  the 
execution  of  an  accurate  movement  the  afferent  elements  are 
most  important.  Coordination  and  the  production  of  accurate 
movements  are  brought  about  largely  through  the  association 
of  afferent  impulses  with  the  efferent,  and  in  the  coordination 
there  are  many  afferent  elements  associated.  In  connection  with 
the  movements  under  discussion,  the  more  important  (possibly 
the  sole)  sensory  elements  are  the  visual  (including  the  sensa- 
tions or  perception  of  eye  movements)  and  the  musculo-tactile. 
Several  times  in  the  case  histories  it  was  mentioned  that  animals 
which  exhibited  an  incoordination  showed  this  especially  for 
movements  of  grasping  objects  at  a  distance  from  the  body. 
When,  for  example,  objects  were  rolled  toward  the  animal  or 
when  the  objects  touched  any  part  of  the  body,  the  animal  made 
quick  and  accurate  movements,  with  a  degree  of  coordination 


io8  SHEPHERD  IVORY  FRANZ 

apparently  normal.  When,  however,  such  objects  touched  the 
body  and  bounded  away  the  objects  were  not  accurately  grasped, 
but  the  animal  fumbled  in  the  place  on  the  floor  where  the  food 
had  been,  and  in  many  cases  was  not  able  to  locate  the  object 
without  great  difficulty.  At  times,  also,  a  monkey  would  give 
up  trying  to  secure  the  food  which  in  rolling  had  touched  the 
body  and  had  then  bounded  away,  and  it  was  evident  that  the 
actual  coordination  of  movements  which  were  made  with  the 
musculo-tactile  element  alone  was  not  impaired  but  that  the  im- 
pairment was  due  to  some  other  element.  In  the  case  of  the  ani- 
mal which  eventually  became  practically  blind  (monkey  5)  al- 
though food  which  was  held  at  a  distance  of  about  10  to  15  cm. 
from  the  head  of  the  animal  was  not  accurately  grasped,  other 
food  which  touched  the  body  or  the  body  hairs  was  taken  im- 
mediately and  accurately.  Observations  similar  to  these  were 
repeatedly  made  with  all  the  animals,  and  in  every  case  in  which 
there  was  a  marked  degree  of  incoordination  or  of  inaccuracy 
in  adjustment  when  the  food  was  held  at  a  distance  from  the 
body,  there  was  no  inaccuracy  and  no  incoordination  when  the 
food  was  held  close  to  the  body  or  when  it  was  touching  the 
body  hairs. 

We  are  justified  in  concluding,  therefore,  that  the  movement 
disturbances  were  due  neither  to  a  disturbance  of  the  motor 
process  (muscles  and  motor  impulses)  alone,  nor  to  the  lack  of 
or  to  the  disturbance  in  physiological  connection  between  the 
motor  impulses  and  the  tactile  and  muscular  sensations.  In  view 
of  this  conclusion  we  are  forced  to  conclude  that  the  disturb- 
ancesjwere  due  to  a  nervous  factor  connected  with  the  visual 
apparatus.  Here  there  are  two  sensory  elements  which  may  have 
a  part  in  the  disturbance — the  true  visual  and  the  movement. 
The  retention  of  the  ability  of  visual  discrimination  speaks 
against  the  view  that  the  disturbance  was  due  to  a  true  visual 
disturbance,  for  we  are  unable  to  say  that  there  has  been  in 
these  cases  any  constant  visual  disturbance  of  the  nature  of  an 
amblyopia,  nor  even  of  the  nature  of  a  lessened  irritability  (in 
the  sense  of  Loeb).  On  the  other  hand,  there  is  nothing  distinc- 
tive in  the  results  which  absolutely  excludes  this  factor,  except 
that  we  have  found  none  of  the  animals  unable  to  distinguish  dif- 


DISCUSSION  OF  RESULTS  109 

ferent  kinds  of  food  which  have  had  very  similar  color  and  light 
qualities.     If  this  element  were  the  important  one,   I   should 
expect  to  find  that  the  animals  would  not  be  able  to  distinguish 
one  kind  of  food  from  another  which  has  a  similar  color  and 
a  similar  brightness.    This  discrimination  of  food  was  found  to 
be  intact  in  all  animals,  and  the  only  observations  which  may 
be  taken  to  negative  this  conclusion  are  those  of  Dr.  Barnes 
(p.  86).     With  these  conclusions  of  Dr.  Barnes  I  do  not  agree, 
as  I  have  indicated  in  the  proper  place.    It  appears  to  me  unlikely 
that  a  lessened  irritability  (which  must  be  shown  by  a  lessened 
discrimination  ability)  should  have  been  present  in  all  the  animals 
which  showed  the  movement  disturbances,  for,  as  has  been  said, 
all  the  animals  were  able  to  distinguish  one  kind  of  food  from 
another,  and  each  animal  made  a  selection  of  food  when  dif- 
ferent kinds  were  presented  simultaneously.     If  this  factor  be 
excluded,  as  I  believe  it  should  be  from  the  evidence  at  hand, 
there  remain  only  two  elements  which  might  have  contributed  to 
the  disturbance.    These  elements  are  the  sensations  of  the  move- 
ments of  accommodation  (i.  e.,  of  the  lens,  etc.)  in  the  focussing 
of  the  images  on  the  retina,  and  the  sensations  arising  from  the 
movements  of  the  extrinsic  eye  muscles.    We  have  very  indirect 
evidence  of  the  part  which  the  two  afferent  motor  processes  took 
in  the  disturbances  in  the  monkeys.    Observations  were  made  of 
pupillary  changes  in  some  of  the  animals,  and  of  pathological  con- 
ditions of  the  extrinsic  eye  muscles,  but  none  of  the  conditions 
was  constant.     We  are  unable  to  determine  the  sensory  losses 
in  these  fields  in  animals,  on  account  of  the  lack  of  information 
which  the  animal  can  give  us,  and  on  account  of  the  inability  to 
judge  of  the  focussing  and  of  accommodation  abilities  of  the 
animal.    The  evidence  is  too  general  to  exclude  one  of  these  fac- 
tors and  it  appears  to  me  that  the  only  conclusion  which,  under 
the  circumstances,  is  warranted  is  that  the  motor  disturbances 
are  due  to  the  loss  of  or  to  defects  in  the  sensational  elements  from 
the  oculo-motor  apparatus.    That  the  eye  ball  movements  and  the 
movements  of  accommodation  may  remain  normal  even  after  the 
destruction  of  the  corresponding  cortical  center  is  not  unlikely, 
for  we  know  that  these  movements  are  reflex,  and  are  only  affect- 
ed in  a  general  way  by  the  activity  of  the  cortex.    If  the  corpora 


no  SHEPHERD  IVORY  FRANZ 

quadrigemina  remain  intact  the  eye  movements  may  remain  al- 
most normal,  and  they  may  be  produced  in  such  a  way  that  the 
impression  is  obtained  of  complete  and  normal  cortical  control. 
This,  I  believe  was  the  condition  in  the  monkeys  which  I  studied. 

It  is  unfortunate  that  the  work  of  Vitzou  and  that  of  Panici 
are  not  accompanied  by  illustrations  of  the  extents  of  the  lesions 
in  the  animals  upon  which  they  operated,  for  their  physiological 
results  have  certain  relations  with  the  present  work,  which  can 
not  be  discussed  fully  without  the  accurate  description  of  the 
lesions.  We  do  know  enough,  however,  to  be  able  to  say  that  their 
results  resemble  those  recorded  in  the  foregoing  paper  to  an 
extent  unlike  those  of  previous  investigators  with  the  possible 
exception  of  those  of  Ferrier.  The  accounts  of  Ferrier's  mon- 
keys with  occipital  lesions  (see  pp.  14-16)  read  much  like 
those  given  by  me  and  by  the  other  observers  who  had  an  oppor- 
tunity to  study  the  animals  carefully  after  the  operations.  It 
will  be  remembered  that  Ferrier's  animals  could  see  although  the 
occipitals  were  extirpated,  they  ran  away  when  they  were  ap- 
proached, they  avoided  obstacles  which  were  in  their  path,  and 
one  animal  was  able  to  see  sufficiently  well  two  hours  after  the 
operation  to  be  able  to  pick  up  particles  of  food  from  the  floor 
of  the  cage. 

In  view  of  the  possibility  of  the  establishment  of  new  paths, 
possibly  though  lower  centers,  it  is  not  surprising  that  Vitzou's 
animals  were  able  to  recover  to  a  larger  extent  their  visual  ability, 
but  it  must  not  be  understood  that  the  recovery  was  complete,  and 
in  fact  there  is  nothing  in  Vitzou's  work  to  indicate  the  possibility 
of  discrimination  of  a  high  degree.  The  fact  that  animals  may 
relearn  habits  after  the  frontal  lobes  have  been  extirpated  was 
interpreted  by  me  to  be  due  to  the  formation  of  new  paths,  and 
it  appears  to  me  most  likely  that  Vitzou's  animals  also  formed 
new  paths  for  certain  visuo-motor  habits,  even  though  the  occipi- 
tals were  destroyed. 

The  results  obtained  by  Panici  are  most  nearly  like  those  re- 
corded in  the  foregoing  paper,  but  from  the  accounts  of  the  ani- 
mal activities  it  is  impossible  to  determine  how  much  of  the 
visual  functions,  which  he  judged  were  retained,  were  retained 
because  of  the  lower  reflex  connections,  and  how  much  real  dis- 


DISCUSSION  OF  RESULTS  m 

crimination  ability  was  retained.  The  criticism  of  the  work  of 
Goltz  applies  here  as  well  as  it  did  to  the  original  work,  and  it 
may  be  said  again,  as  von  Monakow  has  said,  that  the  retention  of 
simple  eye  movements,  or  even  of  simple  visual-motor  habits,  etc., 
does  not  indicate  whether  or  not  there  has  been  a  retention  of 
vision  in  the  sense  in  which  this  term  is  properly  used.  There  is 
undoubtedly  a  connection  between  the  eyes  and  certain  motor 
centers,  but  we  are  not  able  to  say  that  discrimination  has  taken 
place,  and  without  evidence  of  visual  discrimination  the  interpre- 
tation that  visual  functions  per  se  remain  will  not  stand. 

The  consideration  of  the  results  recorded  by  me,  with  those 
which  have  been  recorded  by  Ferrier,  by  Vitzou  and  by  Panici, 
lead  directly  to  the  conclusion  that  previous  investigators  who 
have  assigned  to  the  occipitals  a  visual  function  have  destroyed 
large  portions  of  the  lobe,  and  have  been  content  to  assign  a 
visual  function  to  its  several  parts  as  a  whole  without  dividing 
it  into  individual  elements.  The  conclusion  is  forced  upon  us 
that  the  lateral  parts  of  the  occipital  lobes,  which  also  have  the 
calcarine  type  of  cortex,  have  not  a  true  visual  function  but  a 
function  in  connection  with  the  afferent  impulses  from  the  eye 
muscles.  This,  it  will  be  noted,  is  not  inconsistent  with  the  results 
of  previous  investigators,  although  it  is  opposed  to  the  conclusion 
that  the  whole  occipital  portion  of  the  cerebrum  is  visual  in  func- 
tion, and  although  it  is  opposed  to  the  conclusion  that  in  this 
portion  there  is  a  projection  of  the  retina,  such  as  Henschen  be- 
lieves. 


SHEPHERD  IVORY  FRANZ 


SUMMARY  AND  CONCLUSIONS 

The  monkey  readily  learns  to  discriminate  colors  if  the  colors 
are  parts  of  objects  to  which  the  animal  attends. 

Extirpation  of  the  lateral  parts  of  the  occipital  lobes  does  not 
interfere  with  color  discrimination. 

Extirpation  of  the  lateral  parts  of  the  so-called  visuo-sensory 
cortex  in  the  monkey  does  not  produce  disturbances  of  a  true 
visual  character. 

The  destruction  of  the  lateral  parts  of  the  occipital  lobes  is 
followed  by  disturbances  in  coordination  of  movements  which 
are  based  upon  the  sensations  from  the  eye  and  its  appendages. 

The  disturbances  in  coordination  are  not  due  to  a  lack  or  to 
a  loss  of  the  true  visual  element,  but  to  a  lack  or  to  a  loss  of  the 
afferent  motor  elements,  viz.,  those  from  the  intrinsic  or  from 
the  extrinsic  eye  muscles. 

One  animal  in  which  the  cortex  surrounding  the  calcarine  fis- 
sure was  destroyed  showed  a  true  visual  disturbance  correspond- 
ing with  those  described  in  man. 


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